Jeffrey LewisDick & Matt on the P(Terror Farm)

Speaking of that ranch in Montana …

Dick Garwin tells Congress that, in his formidable opinion, the chance of a successful terrorist use of a nuclear weapon in the United States or Europe is twenty percent per year:

GARWIN: What we are missing is really the response to a terrorist nuclear explosion in a Western city. I think Senator Nunn alluded to this. We need to organize ourselves so that if we lose a couple hundred thousand people, which is less than a tenth percent of our population, it doesn’t destroy the country politically or economically.

But we need to have a way to survive such an attack, which I think is quite likely—maybe 20 percent per year probability, with American cities and European cities included. And we need to be able to survive that. We have no real planning to do it in the business community or in the government.

EDWARDS: I’m sorry. What did you say, Dr. Garwin, the probabilities were? Twenty percent?

GARWIN: Yes, to have a nuclear explosion—not just a contamination dirty bomb—in the next year, 20 percent in my estimation. Could be 10 percent, not 100 percent.

EDWARDS: If that doesn’t wake up this country, I don’t know what would.

[Full text in the comments]

As co-author (with Peter Zimmerman) of the “Bomb In the Backyard,” I am also worried, of course, about terrorists acquiring a nuclear device. But this is a bit much. Twenty percent change per year compounds to nearly 90 percent chance over ten years and 99 percent over twenty years.

In other words, a virtual certainty.

I would have said the probability was an order of magnitude lower—which is to unlikely but still very dangerous—given the evident difficulty of acquiring the fissile material.

My friend Matthew Bunn’s PhD dissertation, Guardians at the Gates of Hell: Estimating the Risk of Nuclear Theft and Terrorism, includes a detailed, plausible calculation that placed the annual risk at just over three percent. Although the model, as he concedes, isn’t definitive, it does “make explicit the assumptions about the key factors affecting the risk and provide a tool for assessing the effectiveness of alternative policies.”

The calculation also appears as an article, A Mathematical Model of the Risk of Nuclear Terrorism , in The Annals of the American Academy of Political Science 607, September 2006. I’ve stripped out the math, just to give you a little of the flavor:

Suppose, as one plausible estimate, that the factors in the equations for Pc and Rc have the following numerical values:

Number of plausible nuclear terrorist groups, Nn = 2
Yearly probability of an acquisition attempt by a particular group, Pa(j) = 0.3
Probability of choosing an acquisition attempt based on outsider theft, Po(j) = 0.2
Probability of choosing an acquisition attempt based on insider theft, Pi(j) = 0.3
Probability of choosing to attempt to purchase black market material, Pb(j) = 0.3
Probability of choosing to … convince a state to provide material, Ps(j) = 0.2
Probability that an outsider theft attempt will succeed, Pos(j,k) = 0.2
Probability that an insider theft attempt will succeed, Pis(j,k) = 0.3
Probability that a black market acquisition attempt will succeed, Pbs(j,k) = 0.2
Probability that an acquisition attempt from a state will succeed, Pss(j,k) = 0.05
Probability of … convert[ing] acquired items to nuclear capability, Pw(j,k) = 0.4
Probability of delivering and detonating bomb once acquired, Pd(j,k) = 0.7
Consequence of terrorist nuclear attack, Cc = $4 trillion

In this example, the number of plausible nuclear terrorist groups in the world is small, but greater than zero. For simplicity, assume for the sake of this example that the various probabilities are the same for all groups in the set Nn and for all acquisition attempts of a given type by those groups.


With these values, one would expect a significant acquisition attempt roughly once every other year … The probability that such an acquisition attempt would be successful, and would lead to the detonation of a terrorist nuclear bomb somewhere in the world, would be in the range of 5 percent. … The yearly probability of nuclear terrorism would be just over 3 percent. … The probability of nuclear terrorism over a ten-year period, Pc(10), would be just under 30 percent.

Check out the real thing. The Σ won’t bite.


  1. Jeffrey Lewis (History)

    Here is the transcript of the Hearing.

    Federal News Service

    March 29, 2007 Thursday




    REP. VISCLOSKY: The subcommittee will come to order.

    The Subcommittee on Energy and Water Development meets today to hear expert testimony on the U.S. nuclear weapons policy and programs, specifically addressing several new initiatives currently under consideration by the subcommittee.

    These issues touch on some of the most profound responsibilities we in Congress are asked to address. I, for one, am pleased to have the opportunity to hear the opinions of individuals who have considered these issues seriously and were responsible for making similar decisions themselves during their service to our country.

    If I could take just a moment to introduce the panel, we are honored to have before us today as distinguished a panel of witnesses as I have ever had the pleasure of introducing. First, I would like to recognize General James Cartwright, Commander, United States Strategic Command.

    General Cartwright, you are currently charged with supporting the nuclear initiatives we will discuss today, and I do look forward to hearing from you. I know that you have been in high demand this spring as a witness to discuss your many responsibilities before many other committees and subcommittees, although I believe this is a first before Energy and Water. Just for your future reference, General, what do you know about the MOX program?

    GEN. CARTWRIGHT: (Laughs.)

    REP. VISCLOSKY: I will now continue, General, but do appreciate your service to our country.

    We are also very pleased to have Senator Sam Nunn, a Nobel Peace Prize nominee. And I must say that I have only met one other in my life, and it was your partner, my good friend: Senator Lugar from the state of Indiana and distinguished former senator from Georgia. He chaired the Senate Committee on Armed Services from 1987 to 1995, and he is now the co-chairman and CEO of Nuclear Threat Initiative, a charitable organization working to reduce the global threats from weapon of mass destruction.

    Thank you very much, Senator, for appearing today.

    We are also honored to have Dr. William Perry, the 19th secretary of Defense, serving between 1994 and 1997, and now a senior fellow at the Hoover Institute and a professor at Stanford University, with a joint appointment in the School of Engineering and the Institute for International Studies.

    Dr. Perry, it is a pleasure to have you, as well.

    Finally, we are pleased to welcome Dr. Richard Garwin, IBM fellow emeritus at the Thomas J. Watson Research Center. I think that there are only two stories about Dr. Garwin that I will repeat here. Dr. Edward Teller, the principal creator of the hydrogen bomb, credits Dr. Garwin with developing the blueprint in about two weeks’ time or less, which made the hydrogen bomb work. And Enrico Fermi, who first achieved the controlled and continuous chain reaction of the atom, declared that Dr. Garwin was “the only true genius I had ever met.” Though I cannot claim to know Dr. Garwin well, I did meet with him last week on a different issue and found the conversation enlightening. In finishing the introduction, I would hope someday to read as many books as Dr. Garwin has written.

    I’m going to keep the rest of my opening statement very short because I think we will all have an opportunity to discuss the issues during the question period.

    The two most profound decisions that I have to consider, as a member of Congress, are issues of war and peace and the change — potential change in the United States Constitution. In the case of the issues of war and peace, the reality of nuclear weapons demand that the issue of war is addressed with the utmost seriousness. It may be an inconvenient truth, but nuclear weapons are a public policy issue that need to be discussed.

    The United States will continue to rely on a safe and reliable nuclear weapons stockpile as a national security deterrent for the future. However, that does not mean we need to have one more nuclear weapon than is necessary for that purpose.

    It is time that the nation takes a hard look at the national security strategy and requirements that are supported by our nuclear stockpile, and decide whether both will support our interest in deterrents and nonproliferation around the world.

    The Energy and Water Development Subcommittee is responsible for funding the nuclear weapons activities of the Department of Energy’s National Nuclear Security Administration. As such, I know that the DE — DOE Nuclear Weapons Complex is a vital element of our nation’s national security posture. However, it is also a rigid, inefficient enterprise that is in desperate need of a complexwide reform. The same could also be said of the government decision-making apparatus that ties us to our Cold War stockpile.

    So before we embark upon any suggested path or, for that matter, even to take it, I do believe that we ought to address these issues.

    I will ensure that all of your statements are entered in their entirety for the record. And for our purposes today, if we are interrupted with a vote — we will have a series of amendments and proposals on the budget — what the intent of the committee is to do is to have members individually go over and vote so we do not have to break the hearing up.

    But before I recognize our first witness, General Cartwright, I would recognize Mr. Hobson for any statement he has.

    REP. DAVID HOBSON (R-OH): Thank you, Mr. Chairman.

    Welcome, gentlemen.

    This is a great panel. I want to thank the chairman for assembling such a distinguished panel to discuss these issues today.

    Frankly, we’re here today to discuss the future of our nuclear arsenal. Between the four of you, there’s roughly 100 years of collective experience regarding this issue. Today, I’m hoping that we can tap into that knowledge and perspective.

    But equally significant is the fact that we have before us a, quote, “customer,” unquote, of nuclear weapons in General Cartwright from the Strategic Command. And I’m — I just want to say one thing: When we worked another issue, having General Cartwright there was very helpful in the previous — when I was chairman of this committee. And I want to thank you for your help in resolving that issue.

    And you were fresh, strong voice in that and I can remember coming — he came into my office one day and I said, “Are you sure you’re talking to the secretary?” And he said, “Yes, I am.” And he was. Well, I’m not quite sure about that, but he did. And he played a strong role.

    For too long, we’ve heard the NNSA profess that their activities are just a reflection of the “customer’s needs.” I hope that today we hear an unvarnished account of DOD’s mission requirements and how you all believe DOE can best meet them. After all, it is DOD that determines the need for nuclear weapons, and it’s DOE’s job to meet that need.

    At a time when DOE has proposed this ambitious program to develop Reliable Replacement Warheads, coupled with a much less ambitious effort to transform our nation’s nuclear weapons infrastructure, we are faced with the more immediate threat of rogue states and terrorist organizations doing all they can to obtain a nuclear or radiological device. It’s ironic that the very weapons that kept us safe and helped us end the Cold War now may impose the most intricate security issues for the immediate future. This paradox raises several questions I hope we can discuss this morning.

    To achieve the universal goals of safety, security and reliability in a cost-effective manner, should we look to validate and overhaul the DOE weapons complex, irrespective of whether or not we develop a replacement warhead? What is the primary justification for Reliable Replacement Warheads? Is it to meet DOD’s military requirement, serve our nation’s broader security needs, or as a catalyst for modernization and consolidation of the weapons complex? Or is RRW really about exercising our weapons-design capability to prove that we can still design nuclear weapons.

    Another question: Who should bear the brunt of costs associated with RRW, DOD the customer or DOE as the manufacturer? Can we do more than what is promised by the superficial Complex 2030 plan in terms of real cost savings, real consolidation, and finally, real security? And can we accomplish that in our lifetimes and not several decades out in the future?

    And finally, the truly fundamental question, especially in light of emerging and unconventional threats: What is the role of nuclear weapons in the 21st century?

    These are tough questions with complicated answers, but that is why this subcommittee asked you to appear today. I am hopeful that we can have a candid and thoughtful conversation about our nuclear weapons stockpile and supporting DOE. I expect our discussion this morning will provide the perspective we all need, as we discuss this allocation of scarce resources to NNSA after today.

    Senator Nunn, Dr. Perry, General Cartwright and Dr. Garwin, I can think of no subject more daunting, more complicated, and with no greater consequence than our nation’s stance towards nuclear weapons. I want to personally thank you for appearing before us today, and I really look forward to hearing your thoughts. Thank you very much.

    Thank you, Mr. Chairman.

    REP. VISCLOSKY: Thank you, Mr. Hobson.

    General Cartwright, if you’d begin, please.

    GEN. CARTWRIGHT: Mr. Chairman and Congressman Hobson, thanks for this opportunity.

    One of the objectives that we’ve had over the last couple of years is to get this debate up and in front of the public. And as you referred, Mr. Chairman, to my opportunities to testify before a large number of committees here over the past few weeks, one thing that has been a recurring theme is to drive home this discussion: What does deterrence look like for the 21st century?

    And none of us have a crystal ball, but we have some choices. And those choices need to be debated and need to be thought about in a cognitive way and in taking advantage of what this nation does best, which is to bring diversity to the problem — diversity in thought, diversity in options, diversity in the way we think about and move forward into the 21st century.

    Mr. Hobson, Congressman Hobson, you talked to the threat for a few minutes in your opening comments there, and I think you’ve captured it very well. One of the things that has struck us, as we have worked our way through at STRATCOM trying to understand what deterrence means for the 21st century, is the realization that whether you want to document off of the fall of the wall, but starting in the early 90s, the change coming out of the Cold War, and the significance of the events that have occurred and the rapid pace at which they have occurred. And you just look at 9/11 and the Afghanistan conflict, the Iraq conflict, the tsunamis and earthquakes and potential for pandemics, all of which have occurred at a pace and a rate that we have not seen in the past.

    When you take a look at the emergence of what we have in the past called the peer competitor, but the nation states, the thought process associated with how we look at rogue states, terrorist organizations, individual terrorists and extremists, and that broad threat, and the use of our nation’s capability to create a deterrent for the 21st century that devalues some of the things that these people bring to the table. They are empowered by their access to information in an unprecedented way, so they have been able to leverage what has taken nation states years and huge capital, both intellectual and dollars and cents, to develop.

    If you look at the nuclear capability that we have today and the potential of someone being able to leverage available information and God forbid but bring nuclear capability to either a rogue state or to a terrorist organization or an extremist, are all things that we should worry about and things that keep me up at night, as the commander of Strategic Command.

    Against that backdrop, in the 2000 timeframe, we sought to change what was the nuclear deterrent capability to a broader deterrent capability, and we talked about what was called the new triad. But the opportunity to have offensive capabilities that were not just limited to nuclear, but included conventional, and defensive capabilities integrated together to allow regional combatant commanders, from the DOD perspective, to have the ability to tailor an appropriate deterrent message and capability to those who they have to address and not to have a one-size-fits-all capability, which was really essentially where we were with our nuclear deterrent.

    We have started to build those capabilities out over the past six or seven years as we build individual capabilities. And from the standpoint of the conventional side of the house, we have put together what we call a J-series of weapons, but a new class of cruise missiles, both air and sea-launched, have been fielded. New weapons from the JDAM and JASSM, which have brought to the forefront capabilities in the conventional realm better than we have ever had in the past and more credible, which is, really, the heart of having a deterrent is it’s credible.

    In the defensive side of the equation, over the past few years, we have been able to build a missile defense system both from a national perspective for the long-range ballistic missiles, and a system that is now starting to emerge to be able to engage what is becoming the most proliferated threat, which are short and medium- range ballistic missiles.

    To date, they are armed with conventional warheads, but they are widely available; all you have to do is have the cash to purchase them. And eventually it is not a stretch to think that they will be able to deliver weapons of mass destruction on them. They are very short in their time of flight. They react quickly. They emerge, they shoot, and they’re gone. They are what we call a fleeting target.

    This is a difficult threat.

    It is one that is facing more our allies and friends and forward- deployed forces than it is really today threatening the homeland. But eventually those long-range threats are going to emerge and be a problem.

    So against that backdrop, in the 2000 time frame, we also engaged in the opportunity to start to reduce the nuclear stockpile to rebalance this triad in a way that was appropriate. The objective there, in what was called the Moscow Treaty, was to bring our stockpiles down in an unprecedented way. That was focused, and is focused, on those weapons that are operationally deployed, and it only focuses on that sector, but the intent was to bring down, between 2000 and 2012, our stockpiles in a significant manner.

    And 2007, which is where we are today, was the halfway point, so to speak, where we were to go back, reevaluate against the capabilities that we had fielded. Had they come up, in credibility and capability, to match the drawdown in the nuclear deterrent? I will tell you in two cases — first in the drawdown — we are ahead of schedule, and we are moving more aggressively now because we believe things like missile defense and the conventional capabilities have come up in credibility, and demonstrated that credibility in a way that justifies bringing these stockpiles down.

    As we move towards 2012, which was the target area to get to the target amounts of deployed weapons, I see nothing in our way to continue down. I have one operational gap, which I am uncomfortable with and which we are debating, and have for the last two years, and that is to bring to bear a conventional Prompt Global Strike capability.

    Today, our Prompt Global Strike is nuclear only. We need to have an alternative to those nuclear weapons. I know that there are issues and worries about ambiguity on this. We’ve worked our way through that in cruise missiles in the past, we’ve worked our way through that in artillery, we’ve worked our way through that in ships, and we’ve worked our way through that in aircraft. We need to work our way through this in ballistic missiles. We need an alternative to nuclear weapons, because in a Prompt Global Strike, a nuclear-only option is not sufficiently credible to deter the range of threats that we’re going to have to address.

    Now, the debate, I don’t think, has been about whether that comment is right or wrong; the debate has really been more about can we do this in a way that does not escalate rather than de-escalate the conflict — in other words, this ambiguity issue and make sure we drive in the right direction. We’ll work that, but I need, as a commander, the capability to address these targets rapidly on a global scale when it’s appropriate, and an alternative to a nuclear-only Prompt Global Strike.

    The other piece that I’ll — I’d like to just make a couple of comments on is — because I know we’ll get into this discussion — is why, for the Department of Defense and for Strategic Command, the Reliable Replacement Warhead is important. There are a couple of issues here that we have looked at in the drawdown of the stockpile — the operationally deployed stockpile. One is we ought to be drawing down more than just the operationally deployed stockpile. We need to look at this broader than just the context of what is operationally deployed. In that context, we today — based on the development of the stockpile that we have — manage operational and technical risk with inventory. We increase the inventory to ensure that we will not be surprised, either technically or operationally. So if a particular warhead has a flaw or if it is operationally not the right solution for the problem that emerges in front of us, we have two or three alternatives, for which we have a complete inventory, to make sure that we’re ready when the nation needs this kind of capability, and that we have credible capability. That manufacturing approach to business — an industrial approach to this creates huge stockpiles.

    In the conventional side, with precision and with manufacturing processes more appropriate for the 21st century, we have driven down the iron mountains of conventional weapons to have a balance between modularity that allows us, if a component is bad, to move components around. It also allows us to get diversity so that we’re not — we don’t have a single-point failure in any given weapon. And it also allows us to not have to have the huge iron mountains necessary to have two and three replacements for each warhead. That, to me, is critical.

    I talk to you at the attribute level; I’m not the one to ask about how you build the complex to do that. But what I am saying is there are 21st-century manufacturing processes and approaches to business that allow us to manage these problems not with huge inventories, but with smart manufacturing processes to drive down the costs associated with these inventories. And for me, the biggest concern is having this many weapons and having to be able to assure that we can keep them safe and secure. If we can draw that stockpile down, that equates to dollars and cents and people who have to guard and safeguard these weapons.

    So these are points I think that we ought to have a discussion about. These are issues that I believe will have a dramatic effect on the size of the stockpile.

    The other piece on the Reliable Replacement Warhead are the attributes of safety, security and maturity. They will not have as large an effect on the size of the stockpile, but they will have an effect on how we, who handle that stockpile, act around it. And having the safest, most reliable, most secure weapons, to me, are attributes that we should strive for within the boundaries of the regret factors associated with losing one of these weapons.

    Having one of these weapons when they’re handled not necessarily to go detonate, but the idea of making sure that — in the past, we’ve had several instances where we have had aircraft accidents or delivery system accidents where the weapons have been involved in fires and extreme temperatures, et cetera. We’ve always been able to safeguard those weapons. We’ve never had one of them go off when they weren’t intended to go off. We need to ensure we put the best technology possible towards ensuring that is the way it stays.

    And the last piece is security. The security that we have today is very manpower intensive by nature. We have technologies that could help us ensure that nobody gets these weapons, and if they get them, they are unusable. We owe that. The regret factors associated with one of these weapons being compromised are significant. And I won’t go into — I’ll let you build your own scenarios. But we do not want to let these weapons in any way, shape or form, fall into the wrong hands and be usable by someone who could acquire one of these weapons.

    The last point that I’ll make, Mr. Chairman, is — I really believe this with a lot of passion, and Senator Nunn and I have had a lot of conversations about this — is one of the ways to approach this deterrence problem is to get up front before conflict — way before conflict. Efforts like the cooperative threat reduction activity, we need to understand what we did in that activity, and what we are doing, that worked and export that globally to countries — to help countries help themselves start to be able to work at nonproliferation, counter-proliferation type capabilities, police their borders, report to their neighbors when things are moving that aren’t supposed to be moving, detect these things.

    This is a very small dollars-and-cents price for a very large leverage, because if we can build a collective defense against these weapons of mass destruction, we can start to affect this problem much earlier, which is where we need to be.

    And I look forward to your questions, Mr. Chairman.

    MR. NUNN: Thank you, Mr. Chairman, and Vice Chairman Edwards.

    Under your leadership and the leadership of Congressman Hobson, this subcommittee, in my view, has been instrumental in stimulating an overdue and very important debate about the role of nuclear weapons in our national security strategy. And so I commend this subcommittee and your committee for, I think, leading this debate and for working together, even where there are differences, to look at the facts and be careful in the examination and listen carefully to witnesses like our distinguished head of Strategic Command, General Cartwright, and Dick Garwin, and our friend Bill Perry today. So I thank you for giving me the opportunity to be part of this discussion.

    In 1948, at the dawn of the nuclear age, General Omar Bradley said — and I quote him — “The world has achieved brilliance without wisdom, power without conscience. Ours is a world of nuclear giants and ethical infants. We know more about war than we know about peace; more about killing than we know about living.” End quote.

    It was a pretty powerful quote, I think, but if he were alive today, I think it might really surprise General Bradley to know that we’ve made it 62 years since Hiroshima and Nagasaki without the use of a nuclear weapon. But that fact should not give us a false sense of confidence that we’ll make it the next 62 years or, for that matter, even the next 20 years.

    Mr. Chairman, you asked me to try to help frame the broad picture here, and I’ll spend most of my time looking at the broad picture and then certainly be responsive to any questions you have.

    I think it’s important to have a perspective about what we’re doing and what we’re not doing, and the challenges, as well as the threats. We have important efforts under way and we’ve had some successes, including, as General Cartwright just mentioned, the Cooperative Threat Reduction Program; the Global Threat Reduction Initiative, GTRI; the G-8 Global Partnership, which I would give a score of eight or nine on words and a score of about three on deeds, but nevertheless, the words are there; the Global Initiative to Combat Nuclear Terrorism; the Proliferation Security Initiative; the rollback of Libya’s nuclear program; and U.N. Resolution 1540.

    Now, all of those are very important, but from my perspective, the risk of a nuclear weapon being used in the world today is growing, not receding. Let me tell you why: Countries like North Korea and Iran, as we all know, are pushing international will to the very brink by developing nuclear weapons technology and, in the case of North Korea, nuclear weapons. A number of additional countries now are considering developing the capacity to enrich uranium; there are at least seven or eight of them, and there are probably more than that. And if they start that process to do — to enrich uranium — and the reason is ostensibly, in all cases, to use fuel for nuclear energy — a legitimate reason. But it also gives them capacity to move quickly to a nuclear weapons program if they choose to do so.

    Stockpiles of loosely guarded nuclear materials are scattered around the world, offering inviting targets for theft or sale. We are working on this — the Nunn-Lugar program, Cooperative Threat Reduction Program — but I believe the threat is outrunning our response. We’re not moving fast enough. And when I say “we,” I don’t mean just the United States; I mean the world, because this is not just a U.S. responsibility.

    Because of an explosion of knowledge and information throughout the world, the know-how and expertise to build nuclear weapons is far wider and far more disseminated than ever before. Terrorists are seeking nuclear weapons for the same reason terrorists seized airplanes on 9/11: to use them to inflict on the world the greatest possible human suffering, economic loss, and geopolitical chaos.

    The good news is that the potential for conflict between the major powers, and in particular the United States and Russia, has dramatically declined. Though both countries seem reluctant to act on it, which continues to puzzle me, we share many security concerns with Russia.

    The bad news is that there still remains a potentially deadly nuclear threat. Both of our countries still deploy thousands of nuclear warheads on ballistic missiles that can hit their targets in less than 30 minutes — a short-warning, hair-trigger, prompt-launch capability that increases the risk of an accidental, mistaken, or unauthorized nuclear missile launch. And this is particularly true because the Russian warning systems have deteriorated so substantially since the Cold War.

    Mindful of these rising threats and the eroding confidence in deterrence, as we have historically known it, George Shultz, Bill Perry, Henry Kissinger, and I published an article in January in The Wall Street Journal. We believe that we have arrived at a dangerous tipping point in the nuclear era, and we advocate a strategy for improving American and global security. Both nuclear have and have- not states must think anew if we are to prevent a nuclear nightmare. Whether the world recognizes it or not, we are in a race between cooperation and catastrophe.

    Those of us who wrote and endorsed The Wall Street Journal piece — and there were a number of very senior officials, former government officials, who joined in endorsing that piece — we believe that in order to deal effectively with this new and dangerous era, the United States and the international community must embrace the vision of a world free of nuclear weapons and pursue crucial measures toward achieving that goal. We believe that without the bold vision, the actions will not be perceived as either fair or urgent. Without the actions, the visions — vision will not be perceived as realistic or even costly.

    Mr. Chairman, Congressman Hobson and members of the committee, we recommend the following specific steps:

    Number one: We must secure nuclear weapons and material around the world to the highest possible standards. General Cartwright referred to that a moment ago.

    Number two: We should eliminate short-range tactical nuclear weapons — the bombs most likely to be targeted for theft or purchased by terrorists. In my personal view, we should start with transparency and accountability of these type weapons between the United States and Russia.

    Number three: Nuclear weapons should be reduced substantially in all states that possess them.

    Number four: We must get control of the uranium enrichment process for civil nuclear fuel production, halt the production of fissile material for weapons, and phase out the use of highly-enriched uranium in civil commerce.

    Last September in Vienna, on behalf of our organization, the Nuclear Threat Initiative, with the support of Warren Buffett — all important support, I might add, and financial backing — I advanced a proposal for establishing an international fuel bank. Representative Lantos and others are advancing legislation to support the establishment of such a fuel bank, which I hope members of this committee will take a look at and hopefully encourage and support.

    Number five: We must redouble efforts to resolve regional confrontations and conflicts. This, of course, is not an easy task; it’s very difficult. But it is an essential one if we are to stem the incentives for acquiring nuclear weapons in places like the Middle East, Southwest Asia, and the Korean Peninsula. These are not simply regional conflicts; they create tensions and confrontations that shape world security and, I might add, also world insecurity.

    Number six: We should work to bring the comprehensive test ban treaty into force in the United States and in other key states. I believe that we should use the report by former chairman of the Joint Chiefs, John Shalikashvili, and the safeguards that he recommends as a roadmap to ratification here at home.

    Number seven: The United States and Russia should move to change the Cold War posture of deployed nuclear weapons to greatly increase warning time in both countries and ease our fingers away from the nuclear trigger. And I might add, again, here that warning systems are all-important in that regard.

    Mr. Chairman, Congressman Hobson, members of the committee, each day we should ask ourselves, “Is it in the United States’ national security interest for the president of Russia to have only a few minutes to decide whether to fire his nuclear weapons or lose them in response to what could be a false warning.” That is a profound question that we don’t spend nearly enough time thinking about. I would hope that this question would be asked in reverse in Russia, and that we would finally begin to ask it together.

    Number eight, finally, in terms of the steps we advocate: I believe that we must enhance our verification capabilities, policies and agreements, once again restoring and elevating President Reagan’s maxim of “trust, but verify” as an essential component of our national security policy. In my view, we should put at least as much effort into verification — not talking about money now; I’m talking about effort — as we do in missile defense. This includes technology and intelligence, but also policy, agreements and transparency, as well as onsite inspection. All of those are enormously important if we are going to be able to meet the challenges of the world ahead.

    You’ve asked me to specifically comment on the Reliable Replacement Warhead, or RRW. First, I want to make it absolutely clear that I support the science-based Stockpile Stewardship Program and the infrastructure required to maintain the safety, security and reliability of our nuclear weapons for as long as we have them.

    On the RRW itself, if Congress gives a green light to this program in our current world environment — and I stress in our current world environment — I believe that this will be misunderstood by our allies; exploited by our adversaries; complicate our work to prevent the spread and use of nuclear weapons, including the steps I outlined this morning; and make resolution of the Iran and North Korea challenges all the more difficult. Also, I think it will make it more difficult

    Also, I think it will make it more difficult to discourage the many new countries that are right on the tipping point of beginning their enrichment process. I think it will make it harder to discourage them from taking that course and harder to set up an international fuel bank as a guaranteed access to nuclear materials so that we can discourage the proliferation of enrichment capability.

    I’ll leave it to others who have full access to classified material — and I’ve had no access to any of that, in terms of the RRW — to discuss whether there is an urgent and imperative case for an RRW program at this time. And I’m sure there are good reasons — I know General Cartwright has them — but I can only say that I have not seen that urgent case. I can see, however, that we will pay a very high price in terms of our overall national security if Congress goes forward with this program.

    Mr. Chairman, I believe that we need a strategic reassessment of the roles and purposes of nuclear weapons in the 21st century and an urgent change in both direction and in the steps we take. So I think we need to change the vision and the steps and make it clear, both in this country and the world, that we are making those changes.

    This change in direction should precede a congressional decision on RRW, so I would not fund additional work on the RRW at this time; certainly not development and going forward with deployment. This new direction will require presidential leadership and a consensus judgment in the Congress to sustain it.

    Mr. Chairman, Congressman Hobson, and Vice Chairman Edwards, I think this subcommittee has really played a tremendous role in beginning that debate, but as you all know, that debate is just beginning.

    In closing, I believe that the vision and actions must go together. We cannot defend America without taking these actions; we cannot take these actions without cooperation from other nations. We cannot get the cooperation of other nations without embracing the vision of a world free of nuclear weapons, which every president since Richard Nixon has reaffirmed through our nation’s commitment to Article VI of the Non-Proliferation Treaty.

    This is not new; it cannot happen over night. It’ll be a long process done in stages. The United States must retain our nuclear weapons as long as other nations do — any other nations do. But we will be safer, and the world will be safer, if we are working toward the goal of de-emphasizing nuclear weapons and ultimately ridding our world of them.

    Nearly 20 years ago, Ronald Reagan was asked to identify the most pressing need in international relations. In response, President Reagan asked his audience to imagine, in his words, quote, “All of us discovered that we were threatened by a power from outer space — from another planet,” end quote. The president then asked, quote again, “Wouldn’t we come together to fight that particular threat?” After letting that image sink in for a moment, President Reagan came to his point, again quote, “We now have a weapon that can destroy the world. Why don’t we recognize that threat more clearly, and then come together with one aim in mind: how safely, sanely and quickly can we rid the world of this threat to our civilization and our very existence,” end quote.

    Mr. Chairman, Congressman Hobson, members of the committee, if we want a safer world for our children and grandchildren, our generation must begin to answer President Reagan’s question.

    Thank you.

    REP. VISCLOSKY: Senator, thank you.

    Dr. Perry?

    MR. PERRY: Thank you, Mr. Chairman. I would like to submit my written testimony for the record, and if you permit that, I’ll give you just highlights from that testimony.

    At the peak of the Cold War, Andre Sakharov wrote a letter to his Stanford colleague, Sid Drell, in which he said, “Reducing the risk of annihilating humanity in a nuclear war must carry an absolute priority over all other considerations.” And so it did. Indeed, through good management — and I must say good luck — we did avoid a nuclear holocaust during the Cold War.

    Today, the primary threat is nuclear terrorism, and the tools we used during the Cold War are not appropriate in this. In particular, deterrents would not be effective against a nuclear terror group, and defense would not be effective. No matter how well designed our defense would be, the terrorist would not use a missile to deliver the nuclear bomb; he would deliver it with a truck or with a freighter. The good news here, however, is that a terrorist cannot build a nuclear bomb from scratch. So the key to success in preventing nuclear terrorism is to keep them from getting the bomb or the fissile material in the first place.

    The Proliferation Security Initiative was established a few years ago as a cooperative international program to interdict nuclear weapons being illegally transferred. This is a useful program, which I support, but we should never — we should never believe it is likely to be successful in preventing a nuclear bomb from — a nuclear power from smuggling a bomb to a terror group.

    A so-called “tactical bomb” could be put in a suitcase. The plutonium needed to make a bomb as destructive as the Hiroshima bomb is about the size of a grapefruit. There is no interdiction system that exists or in fact that is conceivable that would have a good probability of stopping a clever smuggler from transferring either of those.

    Our government’s near-term strategy should be focused on programs designed to accomplish two objectives: first, reducing and protecting existing nuclear arsenals, and secondly, taking all feasible actions to keep new arsenals from being created. Both of these objectives require concerted effort. I’m going to talk first of all about reducing and protecting existing nuclear arsenals.

    During the period that I was secretary of Defense, I made that my top priority, using a program that had been inspired by two visionary senators: Senator Nunn — with us today — and Senator Lugar.

    Our greatest success with the Nunn-Lugar program was in getting Ukraine, Kazakhstan, and Belarus to give up all of their nuclear weapons. At the time we started this program, Ukraine was the third largest nuclear power in the world. They had more nuclear weapons than England, France, and China combined. Today, they have zero nuclear weapons. At the same time, we took actions, in cooperation with the Russian government, to substantially improve the safeguards on nuclear weapons, material and technology.

    The Bush administration has continued the Nunn-Lugar program, but in my judgment, has not made it a priority. It should be our top priority to strengthen the Nunn-Lugar program and extend it to include all nuclear powers, and to deal with fissile materials associated with commercial power reactors.

    The second challenge is to keep new nuclear arsenals from being created. During the last six years, both North Korea and Iran have substantially advanced their nuclear weapon program, even though the administration has stated that they considered such programs unacceptable.

    Beyond North Korea and Iran, there are several dozen countries who have the capability to build nuclear weapons in a year or two. These nations have voluntarily joined the Nuclear Non-Proliferation Treaty and renounced the building of nuclear weapons.

    But this nonproliferation regime is exceedingly fragile. It is threatened today by the emergence of new nuclear powers — India and Pakistan — and would be entirely undermined if North Korea and Iran proceed unchecked to build their nuclear arsenals. But it could also be undermined by the policies of the two major nuclear powers — United States and Russia.

    Russia has declared that because of the weakness of its conventional military forces, and because of the American deployment of a national missile defense system, that it must depend more on their nuclear weapons. They have renounced their previously stated no-first-use policy. They have remerged their old ICBMs, they have undertaken the development of new ICBMs, and they have maintained a large stock of tactical nuclear weapons.

    The Bush administration, for its part, has requested congressional authority to build new nuclear weapons, most notably the so-called “Bunker Buster”; has not ratified the comprehensive test ban treaty, while still complying with it; and has requested the authority to build a Reliable Replacement Warhead.

    The actions of the United States and Russia have weakened the Nuclear Non-Proliferation Treaty, which was already undermined by the nuclear programs of India and Pakistan, and was being further undermined by the emerging programs of North Korea and Iran. Any attempt to prevent a hemorrhaging of proliferation requires all of the nuclear powers to act in concert, and in particular, requires Russia and the United States to show leadership in complying with the requirement of the NPT for the nuclear powers to move towards nuclear disarmament.

    The op-ed piece that Senator Nunn described was written in that period, and in that regard, I want to associate myself entirely with the testimony of Senator Nunn.

    One specific question faced by this committee is whether to authorize the Reliable Replacement Warhead program. There are two valid arguments for proceeding with the RRW program: that it will maintain the capability of our nuclear weapons designers, which will become important if we ever need to design more nuclear warheads, and it allows the design of a warhead that cannot be detonated by a terror group, even if they were able to get their hands on it.

    Our countervailing argument is that if the United States proceeds to develop new nuclear warheads, it will substantially undermine our ability to lead the international community in the fight against proliferation, which we are already in danger of losing.

    My best subjective judgment is that the proliferation argument outweighs the other two, but I understand that we live in a very dangerous and uncertain world, and I firmly believe that we have to maintain an unequivocal deterrent for the foreseeable future. So my judgment would be different if I thought that our present nuclear force could not be reliably maintained to provide that capability for many decades in the future, which may very well be needed.

    The best evidence I have seen on this issue is that our present nuclear weapons will retain their capability for 50 to 100 years, particularly if we continue to downsize the arsenal. So on balance, I believe that we could defer action for many years on the RRW program, and I have no doubt that this would put us in the stronger position to lead the international community in the continuing battle against nuclear proliferation, which threatens us all. And I believe that our best protection against nuclear terrorism are robust programs to keep nuclear weapons and fissile materials out of the hands of terrorists.

    Thank you.

    REP. VISCLOSKY: Thank you very much.

    Dr. Garwin?

    MR. GARWIN: Thank you for the opportunity to be here. And my whole testimony, which supports the statements I will make, should be in the record.

    So I’m going to talk about how valuable is the RRW program, and these values are not only positive, but negative, so you have a judgment to make. I hope to give you some of the elements of that judgment.

    I address the RRW question in five categories: confidence, cost, safety and security, the health of the laboratory design effort, and the requirement that the RRW be capable of being deployed without nuclear testing.

    First, as for confidence, I don’t agree with the generally stated assumption that confidence in the reliability of our existing nuclear weapons will inevitably decline with time as the weapons age. It’s usually stated that the accumulation of minor modifications will move the weapons farther from their nuclear test pedigree and thus, inevitably, reduce confidence in their performance.

    On the contrary, the science-based Stockpile Stewardship Program — and in particular the advanced scientific computing capabilities that have been procured at great cost over the last 15 years of the Stockpile Stewardship Program, have paid off handsomely — as indicated in confidence in increased pit longevity. Thus, in the passage — in the case of the essential and sensitive thermonuclear weapon primaries, the passage of time has brought greater, not lesser, confidence in pit longevity.

    I remind you of the November 2006 announcement by NNSA that the weapon laboratories had updated their 45-plus-year pit longevity to 85-plus years. Of course, that is not the entire nuclear weapon. There’s also the nuclear secondary and the vast number of non-nuclear components that fail, as components always do, but they are not involved in nuclear explosion testing and they can be tested thoroughly and replaced without compromise of reliability.

    In fact, the stockpile weapons, as gradually modified, are closer to the test pedigree than is either of the RRW designs to a nuclear test explosion. And with the passage of time and the improvement in computing tools, I believe that confidence in the reliability of the existing legacy weapons will increase, rather than diminish, just as has been the case with the nuclear weapon pits.

    It follows that the proposed reductions in stockpile numbers, that are supposed to be enabled by the deployment of the RRW, could more confidently be obtained with the legacy weapons. And such reductions need not wait for the advent and the entry into the stockpile of large numbers of RRW warheads, which would not happen, I estimate, before about the year 2020.

    In fact, even the RRW itself would not allow reductions, in the minds of some people. Dr. John Foster, former director of Livermore, has expressed his discomfort with reliance on any single RRW design in view of the incidents of birth defects or design failures with which we have had experience in the past. And I reference his full quote.

    Now, as for cost, it’s claimed that the RRW program will allow a major reduction in cost of the nuclear weapons infrastructure, in view of the elimination of environmentally problematic materials, of which the most prominent is beryllium, not present in either of the RRW designs. But the RRW will not replace the legacy weapons until some years after the first production unit, and the legacy weapons will need to be dismantled for years after that, so beryllium will still be involved for a long time.

    Ultimately, when the legacy weapons, on the one hand, would need to be remanufactured, or the RRW, on the other hand, if we displace the legacy weapons eventually, simplified manufacturing and assembly procedures of the RRW would almost certainly provide a cost savings. But that’s a long way in the future.

    The Office of Management and Budget has long provided a mechanism for evaluation of a particular program, by means of the discounted present value of the streams of costs and benefits, and that’s what NNSA needs to use in making its decision. And the Congress needs to review such a detailed assessment in arriving at its own responsible judgment.

    Now for safety and surety, we have had weapon accidents in the past. We’ve never had an accidental nuclear detonation but, for instance, in 1962, there was — there were four hydrogen bombs accidentally dropped off the coast of Spain, and two of them — the conventional high-explosive exploded and scattered plutonium. So there had to be a massive clean up at the cost of some tens of millions of dollars.

    U.S. nuclear weapons are much safer since that time. Since we no longer practice airborne alert, there are a lot fewer nuclear weapons, and handling procedures have been improved.

    Since there’s no possibility of nuclear explosion with existing weapons, according to the stringent design criteria, safety concerns and costs of accidents can be folded into the stream of costs and benefits. So I say they’re not a make-or-break proposition, and they won’t show up very high in the cost calculation.

    But surety — security is another matter. This is the resistance of a nuclear weapon to being fired with full or very substantial nuclear yield without proper authorization. Bombs and other tactical weapons in the U.S. stockpile have long had Permissive Action Links, and every U.S. nuclear weapon must require its explosive system to be initiated at two or more points, or else it wouldn’t be one-point safe, which they all are.

    So the concern is that a nuclear weapon might be stolen or otherwise obtained by terrorists or some other group, and over the course of hours, days or months, might be disassembled in an effort to defeat the Permissive Action Link or other surety mechanisms.

    Whether a terrorist acquires a couple of legacy weapons, such as the W76 or the RRW, the weapon could ultimately be disassembled and the plutonium metal recast to make the plutonium sphere for a first- generation bomb. So it is not totally inert; it is not harmless. It is likely that they could not detonate that weapon, but they could mine it. But it may be a more difficult target than the hundreds of tons of highly-enriched uranium, and military and civil plutonium that could also be the target of terrorist activities.

    But just as Livermore has indicated that it may incorporate into the RRW program some of the features of the Los Alamos design, some of the lessons of surety learned from the RRW design effort could be used to further improve surety for existing weapons, by their incorporation in the transport container, for example. Whether RRW goes forward or not, such technical transfusion might significantly increase the surety of existing weapons, and at an early date.

    We won’t be able to do without guns and guards for a long time. Reducing the number of nuclear weapons is a good way to reduce the number of guns and guards, but also technical advances in the cases and environment of the nuclear weapons, not necessarily in the nuclear weapons, can be a big help.

    Now for the health of the laboratory design effort, the RRW competition has been a source of intense stimulation and excitement for the laboratories. It has revitalized the design community and, by its nature, opened and strengthened communication between the nuclear weapon designers and the engineering and production complex, to the great benefit of the U.S. Nuclear Weapon Complex.

    However, this benefit would not be much further strengthened by continuing production of the RRW, nor would this one-time benefit be adequate if there were no further RRW designs. In 10 years, we’d be just in the same place, not having designed a nuclear weapon for a long time, and there would be a call for a new nuclear weapon. There’s already a call for a second RRW for the land-based ballistic missiles.

    Now the question of nuclear testing: The technical question as to whether the weapon can, with confidence, be placed into the stockpile after development, but without nuclear explosion testing, deserves more study. And I must say that the JASON Group, to which I belong, is under contract to study this for NNSA, with the bulk of the work to be completed this summer.

    These are my personal comments, and I make two of them right now.

    The first is a narrow comment reflecting the prominence given to the requirement not to test — that the primary reason for selecting the Livermore design over the Los Alamos design was that it was closer to the test experience. Well, one can have more confidence, and even much more confidence, in A than in B, but that is still not absolute confidence. And I say again that the legacy weapons are closer to their test pedigree.

    A more general comment is that beyond the technical judgment of engineers and scientists is the question whether at some future time, after the weapon enters into service, there may be political questioning by some president or presidential hopeful, or even by some future STRATCOM commander, about the wisdom of having a growing stockpile of untested nuclear weapons. It seems likely that such high-level concerns would lead to a nuclear explosion test despite the U.S. being a signatory to the comprehensive test ban treaty without having yet ratified the treaty.

    But even if the stockpile RRW passed its nuclear explosion test with flying colors, the United States would have incurred the political, proliferation and security costs of having its rivals, and perhaps other countries, conduct nuclear explosion tests that will very substantially advance the state of the nuclear weapons art in their countries.

    The French weapons establishment, the CEA, in its annual report in the early 1990s, stated with pride that they had been able to accept a new warhead for the submarine fleet into the inventory without nuclear testing. However, with the change of administration from Francois Mitterrand to Jacques Chirac, France decided to conduct a quick series of eight nuclear explosion tests at their site in the Pacific. The series was terminated after six tests, and I commented on international radio and television that that test series was not a bad thing if it could lead France to sign the CTBT. And indeed France and the United States vied to be the first signatories to that treaty. In a CTBT era, however, a nuclear explosion by the United States would have major adverse security consequences.

    So as for confidence, I believe that we have at least as much confidence in the life-extension programs of the legacy weapons as we would have in the RRW. And we have proof of that, in regard to the pits, with another 40 years to validate pit production facility at Los Alamos, as well as pit production elsewhere.

    The cost of the RRW program is unknown and must be broken down into work packages and evaluated on the discounted present-value approach. RRW can incorporate advances in surety. Legacy weapons are safe enough, especially in view of reduced numbers and lack of weapons alert. Surety improvements in the RRW are sound, but not absolute, and some of them can be incorporated into the weapons environment of the existing weapons.

    The laboratory design effort has been reinvigorated, but that is already accomplished. And the question of nuclear testing is all- important. U.S. national security would almost surely be impaired if, after RRW was deployed, it had to be tested.

    Thank you for the opportunity to talk with you.

    REP. VISCLOSKY: Mr. Garwin, thank you very much.

    And I will thank all of the panel. I thought your testimony was just enlightening, which does, as you know, not always happen.

    Couple of just comments I would make, and then I would have one question to begin with, is that Senator Nunn, you talked about the committee’s involvement in this issue and congratulated on us.

    I was remiss by not referencing my good friend and partner, and that is Dave Hobson. Because I do think the reason we’re all in this room today is there was a House report by this committee in 2005 that asked the administration to look at the complex. And the administration looked at the complex, so you had the Overskei report that came of it. And essentially now we are having a very serious conversation about the RRW — this afternoon as well as this morning — serious discussion about the characteristics, size, and need of the nuclear complex. I don’t think that would have happened but for the leadership and foresight of Mr. Hobson, and would note that.

    Dr. Perry, you had also referenced the Bunker Buster. I was going to try to control myself, but would also note that, again, one of the joys, as a member of Congress, is having had the good luck to be here with Mr. Hobson, who chaired this committee for four years. And he has taught me well in that. If he believed the president of the United States — in this case President Bush — was correct on an issue, he would go all the way down that road with the president of the United States. And if he thought that he had a disagreement, he would go all the way down the road on that — in this case the Bunker Buster.

    And I’d like to think, and I do believe, that that is the attitude of everybody on this subcommittee, too, and we’re just trying to find the right thing.

    So Dave, I just wanted to mention that.

    Several of you also talked about nonproliferation, and just for the record at the beginning, would point out that in the administration’s request for 2008, while there is an increase request for weapons activity of $235.7 million, there is in fact a decrease in the request on the nonproliferation accounts of $10.7 million.

    The last point I would make — and the Stockpile Stewardship Program was referenced by several of the witnesses and we’ll have more detailed conversations about that in the afternoon — is one of the concerns I do have is Congress was told that we needed a number of facilities built to facilitate the option of not testing, but to make sure that we did have safety and reliability. But the National Ignition Facility, Microsystems and Engineering Science Applications building, and the Dual-Axis Radiograph Hydrotest Facility still are not yet completed, and now we have a new request before the committee to change course somewhat.

    But having said that, General, if I could start. The American Association for the Advancement of Science panel on the Reliable Replacement Warhead released an interim report in February of this year and recommended any decision to proceed with the RRW must be coupled with a transparent administration policy on nuclear weapons, including comments concerning stockpile size, nuclear testing and nonproliferation.

    The Defense Science Board’s study on nuclear capabilities and the Defense Threat Reduction Agency’s sponsored report on foreign perspectives, released about a year ago this time, pointed out that there has been virtually no high-level long-term articulation of U.S. nuclear weapons policy.

    The DOD and DOE are aggressively implementing the RRW initiative in planning for a long-term nuclear weapons complex modernization effort, although the administration has not announced any effort to begin a policy process to reassess our nuclear weapons policy and the future nuclear stockpile required to support that policy. I do believe this is the cart before the horse, and you had even mentioned that the Moscow Treaty refers to deployed weapons and that we, as a country, need to look more broadly.

    The fundamental concern I have here is until we have a determination recognizing that the objective potentially evolves on a daily basis, where we should be at a point in time, as far as nuclear weapons, and then decide exactly how we should get there.

    GEN. CARTWRIGHT: A little bit of an awkward position in talking about policy, but we have as a department conducted both the collecting of defense — (off mike). Both of those have put us on —

    REP. VISCLOSKY: Microphone, please.

    GEN. CARTWRIGHT: Am I not close enough?

    Both of those put us on a path, as I stated in the opening remarks, towards the lowest number of nuclear weapons necessary for national security. Both of them — both of those reviews put us on a path to start to better integrate the other offensive and defensive capabilities available to the department, both in established programs of record and in those that are proposed in the future, to allow us to get the lowest number of nuclear weapons necessary for national security. I broadened that out in my comments, and certainly in my interpretation as a commander, to be more inclusive than just those that are operationally deployed.

    Having said that, trying to find, one, credible deterrent capabilities across this broad spectrum of threat that are alternatives to just a nuclear deterrent is a lot of the work that STRATCOM has endeavored in filling out what is called the “New Triad” — (inaudible) — the capabilities in missile defense, our mission area in combating weapons of mass destruction — which is the nonproliferation and counter-proliferation consequence management missions — has given us credible alternatives across this broader spectrum where, in particular, nuclear weapons are not appropriate.

    We still have some capabilities that we need to field or find capabilities against — as you articulated, the individual terrorist who is not likely to use an ICBM as a delivery vehicle — against having alternative capabilities, where we had heretofore only relied on nuclear weapons, and yet have a threat, particularly in the sophisticated adversaries, but also in the relatively unsophisticated adversaries.

    So in both cases, I think we’re on a path to start to draw down these weapons. We have endeavored over the past two to three years to get this debate to be a little richer than it has been and more broadly discussed. That has actually been quite advantageous in moving us forward in finding credible alternatives to a nuclear-only strategy.

    Does that work need to continue? Is it done? It is not done and it does need to continue. We have tried in the policy — in our participation, from STRATCOM perspective — in the policy debate to ensure that it is broader than just nuclear, and oftentimes we had stovepiped nuclear discussions to be nuclear-only discussions and not considered the other pieces of the puzzle — things like the Proliferation Security Initiative and the cooperative threat reduction activities have to be a part of this debate, as do conventional capabilities, as we deploy them into our forces across the spectrum of threats.

    So to me, broadening this debate out, understanding the breadth of the threat that we’re trying to address, alternatives to nuclear weapons that can be plausibly put in place, allowing us to draw down that nuclear weapon stockpile to the smallest number necessary for national security is the policy that I am charged with trying to, one, create capability for and two, create credibility in that capability.

    REP. VISCLOSKY: And you’re pursuing that policy, but the question really is, is there a clearly articulated administration decision in determination as to if, in that configuration between conventional and nuclear, what the stockpile should use, as far as what it should be per its characteristics, how many systems are contained in it, as well as how many warheads and what the status of those warheads. Is there a clearly articulated administration policy on that point?

    GEN. CARTWRIGHT: Let me put it in this context: One is to

  2. anon rev

    I’m prepared to credit Matt Bunn as Doctor of Nuclear Philosophy, but his “Mathematical Model” is pseudoscientific and at best a framework for analysis. His “plausible set” of numbers are seemingly chosen freely to give a “plausible” answer, in other words, a guess which is no better than that of Richard Garwin (an actual scientist). Apart from building a structure on which to hang various arguments about what factors are the most important or the best targets for improving nuclear security, Bunn might have given some deeper analysis of the stability of his result with respect to changes in his assumptions, including the values of his parameters, possible correlations between them, and the structure of the model itself. Would a somewhat different way of factorizing the problem lead to different results? How about a dynamic approach, instead of a static probability assumption? Are the various players just sitting around rolling dice, or are they engaged with one another in a continually changing strategy game?

  3. Geoff Forden (History)

    It is, of course, very hard to argue with specific selections of numbers for each of the different contributions so lets, for the moment, accept them all. Now, lets run the calculation backward in time to see what the probability would have been of a nuclear terrorist attack after the fall of the Soviet Union to now (a period of 16 years). Actually, given the increased—but still not perfet—security of Russian nuclear weapons the probability of a nuclear terrorist attack should have been larger for the previous 16 years than it will be for the next 16 years. This calculation is important because, while we might not have a good sense of the net future probability, we can make some interesting comments on the past period where we know Al Qaeda’s past activities.

    The numbers presented here says that the probability of such an attack was 42%, or nearly 1 out of 2. I dont believe we were in that much danger. After all, Al Qaeda attacked the US using conventional means. Furthermore, they actively discouraged Jose Padilla from a nuclear attack saying that it was unrealistic.

    So in the past, Al Qaeda judged probabilities of a successful nuclear terrorist attack as much less than 50%, perhaps a self-reinforcing judgement but nevertheless I think it implies that the numbers presented here are too large.

    I would question the numbers for success of theft attempts. Perhaps a better estimate for those would be down by a factor of 10. (Im not sure about the 5% probability that a nation would give a terrorist group a bomb but that too might be a factor of 10 too high.) If so, then the yearly probability drops to 0.3% per year.

    Let me be clear, I am not saying that just because we have not had an example of a nuclear terrorist attack in the past 16 years means the probability is low. I am saying that Al Qaeda assessed the probabilities as much lower than the example gives over the past 16 years when it was much easier to get nukes means the different components in the example are too high.

  4. Ak Malten, Global Anti-Nuclear Alliance (History)

    Dear Jeffrey Lewis,

    here is a link to an European study done by Mycle Schneider, International Consultant on Energy and Nuclear Policy, about the risk of Nuclear Weapons Proliferation in a Rapidly Changing World, which deals with this issue. It is called:

    The Permanent Nth Country Experiment –– Nuclear Weapons Proliferation in a Rapidly Changing World

    It can be found at:

    Peace, orsaved bythe pigeon,

    Ak Malten,Global Anti-Nuclear Alliance

  5. John Field (History)

    Let’s assume we know nothing at all about the yearly attack probability(except that it’s between 0 and 1). Averaging over a uniform distribution, then, the odds that Garwin’s numbers are right would be:

    1 in 44 for p>20%1 in 6 for p>10%

    And, the expected value of p would be about 5.5% per year. This does not confirm Matt’s calculations, but it is consistent with them. At the same time, Geoff’s comments are consistent with the observed facts also.

    The only person who is inconsistent with the observed facts is Garwin.

    I don’t doubt that Garwin could well be the world’s expert in these matters. Nonetheless, his comments seem to conflict with observations at the 95% confidence level. That doesn’t mean that he is wrong, just that he needs to articulate more facts for his estimate to be credible. For example, he could argue that the risk is getting higher over time, or that there is a 10 year lag time, or something like that.

    I assume that Garwin would say that his estimate cannot be extrapolated past about 5 years due to skewness in the probability distribution of probabilities.

    Lacking support though, I think Garwin’s estimate is not credible.

  6. Andy (History)

    While an interesting academic exercise, I fail to see any pragmatic utility in attempts to calculate the probability of a such a scenario. It’s great for politicians and those in the Homeland Security industry to secure funding and contracts but not much else. Additionally, given the significant assumptions required to generate a “yearly attack probability” the method’s accuracy is suspect at best. No accuracy + no precision = no utility in my book.

  7. Matthew Bunn (History)

    I suspect that some of the commenters have read Jeffrey’s summary and the comments, but not the actual article. The article makes it very explicit that all of the input parameters are profoundly uncertain, and that the utility in such a model comes from using it as a tool to try to think through systematically how different factors and different potential policy interventions might reduce the risk, NOT from the particular probability estimate that results from the set of input parameters I use as an example (which is described in the article ONLY as an example of the use of the model). In my view, such a model can help make the discussion more systematic, narrow the range of disagreements, and identify promising areas for policy intervention and for collection of additional information to reduce the uncertainty. As far as I am aware, the article represents the only available discussion that at least attempts such a systematic approach, and walks through what little evidence there is about what the values of each of the input parameters of such a model might be. (And it does include, contrary to the suggestion of some commenters, some extended discussions of the sensitivity of the results to changes in the input parameters.)

    I find it particularly interesting that some commenters are willing to sling quite serious charges like pseudo-science without being willing to attach their names to their remarks. I would prefer to keep the debate on a more substantive level.

    I’m afraid I don’t understand Geoff’s argument that the record shows al Qaeda estimated a less than 50% chance of success over the past 16 years. At no time during that period, as far as we know, did al Qaeda actually acquire nuclear bomb material, despite multiple attempts to do so; in the absence of such material or of a nuclear weapon, its chances of succeeding in launching a nuclear attack would obviously have been zero. The fact that they didn’t think Jose Padilla could make a nuclear bomb likely reflects a correct judgment of his very limited capabilities, not necessarily a judgment about what other groups of operatives might have been able to do. (However, the fact that in those discussions, even quite high-level al Qaeda operatives apparently suggested using uranium in a dirty bomb suggests that at that time those individuals, at least, had quite a limited understanding of nuclear matters.) Anthony Wier and I discuss the record of al Qaeda’s efforts (what little of it is publicly available that is), as well as Aum Shinrikyo’s, in “The Demand for Black-Market Fissile Materials,” available at

    I believe that when one examines the specifics of security arrangements at nuclear sites around the world and the kinds of insider and outsider threats they would likely be able to defend against, and the kinds of capabilities that terrorists and thieves have shown they can put together to successfully attack or steal from guarded facilities, it is very difficult to sustain the argument that the real probabilities of successful thefts are an order of magnitude lower than those I postulated. What I believe we should be trying to achieve is a world in which these probabilities ARE an order of magnitude lower (or even two orders of magnitude lower) than those I postulated, and the risk of nuclear terrorism correspondingly lower, but I think we’re a long way from being there so far.

    Geoff is quite correct in saying that nuclear stockpiles in the former Soviet Union were less secure in the 1990s than they are today. I would add an additional factor: then, al Qaeda had a centralized command structure with a secure national home base, which probably gave it a higher chance of carrying out something as complicated as a nuclear weapons project than they have in their current, more scattered state (though unfortunately that only reduces, but does not eliminate, the risk that a cell such as the one Jeffrey and Peter described in their “Terror Farm” article could pull off such an enterprise).

  8. Andy (History)


    I did read the article and I still stand by my comments. If, as you admit, the input variables are “profoundly” uncertain then of what use is any yearly probability calculation based on those variables? What use is a systematic methodology if the conclusion will invariably be suspect? The issue with policy, in my view, is that with such uncertain variables, policymakers are likely to pick numbers that support their predisposed policy objectives. Rather than informing policy, your system is much more likely to be misused by those who control budgets and policy. But maybe I’m just cynical.

    Another issue I have is extrapolating an already dubious single-year probability out to ten years or more. In such a case small differences in a few parameters can multiply into great disparities over a decade. (I read the article on LexisNexis, which did not include the actual equations, unfortunately) Such extrapolation ignores that parameters will change significantly over time and therefore change the extrapolated probability.

    Even if you had left out the overall probability calculation and focused exclusively on the parameters themselves there are still significant problems. For example, the article states, “It also makes it possible to identify policy options to modify each of the parameters to reduce the risk and to explore quantitatively what the effect of such policy options might be.” The problem here is the effect of a particular policy option on a particular parameter or parameters comes down to judgment. How does one quantify, say, the installation of new physical security measures at a particular site or multiple sites? Or the allocation of money to Russian nuclear security? It’s easy to say that such policy options will likely improve nuclear security and reduce the probability of an attack, but it’s a much more difficult proposition to identify by what degree security is improved and more difficult yet to quantify that judgment into a precise number.

  9. Matthew Bunn (History)

    Because systematic estimation is difficult does not imply it’s worse than relying on intuition. I continue to believe that a systematic approach helps in focusing the discussion, identifying areas of disagreement, identifying areas where additional information would reduce the range of uncertainty, and, yes, offering an at least somewhat more focused approach to assessing which policy options might be most important. I claim neither more nor less.

  10. Andy (History)

    That’s quite reasonable Matthew. My perspective as someone who spent a career in Intelligence is that no system, no matter how thorough, well-thought out or systematic can make up for a fundamental lack of data. I’ve seen similar methodologies which may provide value to analysts misused by policy makers to reach and justify unsupported conclusions. That is the danger based on my experience. I can only hope that some agenda-driven think-tank does not use your systematic approach to further its agenda.