Sam BlackNuclear Threats

Stimson has just published a report on the history of nuclear threat-making that was a project of mine for a few months earlier this year. It’s about 30 pages long, including the data set, so I thought I’d provide a summary of the findings, with a focus on a few things of particular interest to this community.

I focused on threats made during crises or wars between 1970 and 2010. Threats were defined so as to include both observable actions taken (e.g. increasing alert levels, forward-deploying nuclear-capable forces) and statements by high-ranking executive branch or military officials. The choice to study threats made in crises or wars was driven in part by a fear that including threats made in less tense times would include a lot of cheap talk – if making a threat doesn’t bear a risk of inadvertent escalation, the party making it doesn’t face any costs. So the focus on crises and wars helps avoid some “threats” that have more to do with domestic politics than anything else (though obviously any public statement by a politician reflects at least some consideration of the statement’s domestic impact).

There are lots of caveats which are discussed at length in the full report, but there’s one that I want to note here as well. In any quantitative study of nuclear threat-making, you’re going to face a choice: to include all signals that might plausibly have been interpreted as being nuclear threats by the target, or to rely on case studies to restrict the list of possible nuclear threats to ones that were demonstrably intended or interpreted as such. In the first case you’ll be able to stick to a set definition. In the second you’ll have a smaller data set that is more reliable, and a lot of borderline cases, because the burden of proof will be high and the evidence will likely be thin, especially for political systems in which information of this sort is not readily available. I opted to stick to a set definition, which led to the inclusion a few strange cases (the 1977 threat against Guatemala comes to mind) but also provided some benefits. These included being able to use a definition which provided a clear reason for including some threats and excluding others, rather than making a judgment call on each and every data point. The inclusive approach also yielded a perspective which focuses more on the vast majority of countries that don’t possess nuclear arms (since it includes all events that they might plausibly have interpreted as being nuclear threats).

All that being said, I’ll turn to the findings. The most significant of them, to me at least, was how infrequently non-nuclear weapons states that are in compliance with their nonproliferation obligations are threatened with nuclear weapons. There were 9 threats against NNWS in compliance with their nonproliferation obligations in the 1970-1990 time period, 36% of all nuclear threats during that period. There were 7 between 1991 and 2010, and these comprised just 13% of all nuclear threats in the last two decades. The significance of this finding is even more important given the political positions taken by these states. The NNWS regularly demand legally-binding assurances against the threat or use of nuclear weapons against them. Yet they have never been freer from nuclear threats, at least during crises or wars, than they are now.

So what do we make of the NNWS’s demand for legally-binding negative security assurances? Two-thirds of all nuclear threats against NNWS in the last two decades were against states that possessed chemical or biological weapons or against states that failed to live up to their IAEA safeguards commitments. It’s unclear to me how the vast majority of NNWS which are in compliance with their nonproliferation obligations benefit from demanding benefits which would mainly protect the least compliant of their colleagues. One possibility is that the NNWS have so little confidence in the ability of the nonproliferation regime to prevent their neighbors from acquiring WMD that they are trying to remove obstacles to being able to do the same, if necessary. Another possibility is that the NNWS don’t think that nuclear threats have much of an effect on the actual ability of their colleagues to acquire WMD, and would simply prefer to keep regional tensions as low as possible. Thirdly, it could be that it is the existential threat from nuclear weapons rather than nuclear threats during crises or wars that most concerns the NNWS.

The bigger picture isn’t something discussed much in the report. A smaller group of states is responsible for a much larger share of all nuclear threats during the 1991-2010 time period than during the preceding two decades. And furthermore, in the last twenty years, nuclear threat-making has been concentrated across a smaller number of crises and wars involving this same small group of states. What appears to be happening is that nuclear threat-making is becoming confined to a small number of political conflicts that are more removed from the normal course of international relations than before.

Two specific types of conflicts – the narrow one between India and Pakistan and the broader one involving America’s efforts to prevent WMD proliferation – were responsible for a much, much larger proportion of all nuclear threats between 1991 and 2010 than any other pair of conflicts in the previous two decades. If nuclear threats are less dispersed across countries and conflicts now than they were before, but the overall number is up, the crises or wars that do involve nuclear threats will involve more of them per crisis or war. I would argue that when a crisis involves multiple threats to use nuclear weapons, this is a symptom and/or cause of increased escalatory potential. Thus, those with a stake in preventing the future use of nuclear weapons would do well to pay attention to these particularly dangerous political conflicts.


  1. FSB (History)

    you say: “The most significant of them, to me at least, was how infrequently non-nuclear weapons states that are in compliance with their nonproliferation obligations are threatened with nuclear weapons. ”

    OK. Another study to carry out is whether the findings of compliance or non-compliance are objective or whether they are, perhaps, tainted by political motivations, and domestic lobbies, with the willing blind eye of a complicit media. Once that study is done, then your conclusion above can be examined more rigorously.

    The media angle, especially regarding the wrong reporting by New York Times reporters David Sanger and William Broad, on IAEA’s inspection and monitoring work in Iran is here:

    see also:

    The problem, as I see it, is this: the permanent UNSC members are also the NWSs. The UNSC also has great sway over the IAEA — for more on that see:

    So the UNSC can unite to find a NNWS non-compliant. I am not saying that it is easy: it was very difficult for the US to get all the P5 members on board, since the evidence was non-existent and the legal basis was absent, but the conflict of interest is there.

    The agency that determines a finding of compliance or not w/r/t a NNWS, should be *completely insulated* from political pressure from the NWS, who have the power to threaten with nuclear weapons the NNWSs.

    The opposite is now true (it was not always the case): The IAEA is tainted by its *effective*, if not official, subservience to the UNSC/NWS.

    You go on to mention: “The NNWS regularly demand legally-binding assurances against the threat or use of nuclear weapons against them. Yet they have never been freer from nuclear threats, at least during crises or wars, than they are now.”

    Well, OK but I am not sure of the implication: should NNWS cease and desist from demanding NSAs?

    Yes the nuclear taboo is getting stronger perhaps, but NSAs should still be given.

    And BTW, when are the NWS getting rid of their nukes as outlined in the NPT from the 1960s? Looks like the Republicans in the US are forcing the US to be non-complaint w/r/t the NPT. Is the US going to get reported by the IAEA to the UNSC?

    Can the UNSC sanction one of their own P5 states, when each P5 member has veto?

    • sam (History)

      FSB –

      I’d have no problem with the study you mention in theory. But any study judging the politicization of decisions of international organizations will be inherently political. Unless you have a really stellar, respected group of authors carrying out the study, it will just be another political shot from one side against another. In any case, my study notes that countries that have been labeled, fairly or unfairly, as having troubling compliance records, are subject to a larger proportion of nuclear threats that target NNWS. I think it’s important conclusion regardless of the process of labeling noncompliance (because if the process is unfair, it means its outcomes are all the more significant and unfair).

      On NSAs: I didn’t mean to imply that the NNWS shouldn’t be seeking them. It’s their prerogative to take political positions. I merely observed that this political position provides benefits mainly to a small number of states within a large group, and was interested about what others in the group thought they had to gain from using political capital to achieve this goal.

    • FSB (History)

      Ok, however, what I am saying is that the fact that the same states that make the nuclear threats are the ones with the power to influence decisions on findings of non-compliance makes your conclusion unsurprising.

      I am not saying there is no value to what you did — I am saying it is unsurprising and could have been predicted, but I am gald you did it.

      of course, if a NWS (especially a powerful one, hypothetically let’s take the US) is particularly interested in harassing a given NNWS (hypothetically let’s take Iran), then it has a mechanism (membership in UNSC, UN purse-strings, and political/economic influence over other UNSC members) whereby it can influence the very agency that makes the findings of non-compliance, and thus open the door to threats: nuclear threats, sanctions etc.

      This has already happened with Iraq and Iran.

      Perhaps the IAEA should not even be part of the UN.

      The fact that few states that are in compliance have been threatened could be due to the fact that those states that any of the NWS are interested to threaten can, with enough will and political and monetary might, be unfairly found to be in false non-compliance.

  2. Scott Monje (History)

    “It’s unclear to me how the vast majority of NNWS which are in compliance with their nonproliferation obligations benefit from demanding benefits which would mainly protect the least compliant of their colleagues.”

    The point would be valid if there were a substantial cost to demanding NSAs or a substantial benefit to be derived from refraining from such demands, but I don’t see what those would be.

  3. John Schilling (History)

    I don’t fundamentally disagree with the conclusion, but I think it is weakened by the methodology. In particular, the decision to assume any deployment of nuclear-capable forces constitutes a nuclear threat unless proven otherwise. The vast majority of the world’s “significant
    military forces capable of employing nuclear weapons” over the period of the study, consisted of tactical fighter-bombers, artillery batteries, etc, that could in principle deliver nuclear weapons but whose primary mission and actual operational use was purely conventional and whose deployment carried the unmistakable message, “do as we say or substantial quantities of TNT will be coming your way”. Sending MiG-21s to the Suez, is simply not a nuclear threat in any credible sense.

    You justify this on the grounds of objectivity, but it doesn’t seem any more or less objective, it merely shifts the subjective part to evaluating the excuses, the specifically and clearly meant for a different purpose” part of your formulation. A Royal Navy frigate with maybe a couple of nuclear depth charges sails towards Guatemala and this constitutes a “nuclear threat”; a battle fleet with multiple aircraft carriers and a vastly larger nuclear arsenal sails towards the Falklands with more clearly hostile intentions and this is not a nuclear threat, on the grounds of a government statement that is conspicuously silent as to exactly which sort of bombs would be dropped in the course of retaking the latter? This is not objective, and it is not credible.

    It is relevant. If we hope to move towards a world where nations which abide by the NPT are not subject to nuclear threat, it is nontheless necessary to recognize that they may legitimately be subject to conventional threat over any conventional misbehavior. Deploying e.g. an aircraft carrier or a fighter wing, is a very common means of delivering such a conventional threat, and I do not belive it is commonly mistaken as a nuclear threat in the real world. It probably ought not be mislabeled as such in policy discussion.

    Yes, this would require a bit of subjectivity. I don’t think there is any way around that.

  4. sam (History)

    Scott – my assumption, which may be incorrect, was that the more demands the NNWS issued, the less likely it would be that any particular one of these would be satisfied. So not seeking this one might facilitate the attainment of other goals.

    John – subjectivity is indeed required. There’s no doubt that many of these cases do send mixed messages, as the movement of any unit capable of using both nuclear and conventional would. As I mentioned, I chose to include these mixed messages. The point of including mixed messages in a study of this type is that in the absence of clear intelligence that the Mig-21s (for example) weren’t intended to delivery a nuclear payload, many analysts and planners would have had had to assume that they were. I can’t say this based on first-hand experience, but I don’t recall reading much about the US assuming the Soviets had good intentions. And during crises or wars, assumptions of good intentions would be even less likely than before. So though conventional threats are indeed delivered by dual-capable units, I don’t believe that my coding was not objective or credible. Bad intelligence and worst-case assumptions are not uncommon.

  5. Alex (History)

    I somehow doubt anyone thought either the Falklands or Guatemala were nuclear scenarios. For one, that’s berserkly non-credible. For two, a nuclear depth charge implies a submarine target worth using a nuclear bomb for. Guatemala in 1977? Think not. For three, Argentina had precisely one modern submarine in 1982. For four, NDBs weren’t UK National assets but NATO ones under control of SACLANT (or SACEUR/COMNAVNORTH depending on the exact details).

  6. John Schilling (History)

    The Falklands might be a borderline case, in that the Vulcan bombers deployed to Ascension and used in the Black Buck raids were primarily nuclear delivery systems with a secondary conventional role, and I don’t recall the British saying or doing anything to explicitly rule out the “we will retake the Falklands by nuking Argentine military bases until they decide to give up” plan.

    We now know that this never was the plan, and it would have been unlikely even with what was publicly known then, but as a response to an invasion of “sovereign British territory” in the era of tactical nuclear warfighting doctrine it’s not wholly out of the question that Galtieri might have believed such a thing – or that the British might have hoped he would.

    Guatemala 1977, yes, that’s just bizzare.

    • Alex (History)

      I mean, if you want to go for this sort of maximalist definition, the UK made a continuous nuclear threat to Guatemala for 20 years, as there was a permanent detachment of RAF Harriers based at Belize City in support of the British infantry battalion group there. And the Harrier is “nuclear capable”!

      In that it has a NATO-standard hardpoint that will take the weight of a WE177, and that the mission profile for delivering it had been established for the NATO Central Front and Northern Flank missions.

      The menace over Guatemala is now at an end, as the WE177s were destroyed in 1998. Similarly, until the NDBs were withdrawn, each and every Navy Lynx or Sea King 2 or 5 heli was technically “nuclear capable”.

      Of course, with things like the SADM, the notion of “nuclear capable delivery platform” encompassed a pair of boots. That’s a reductio ad absurdum, but it’s handy to know when you’re being absurd.