Jeffrey LewisArsenals of Folly

I am about halfway through Richard Rhodes’ new book, Arsenals of Folly.

I am enjoying it tremendously. My favorite moment, though, comes in the discussion of overkill in US nuclear strategy:

Robert McNamara, for example, visited the Omaha offices of the Joint Strategic Target Planning Staff for a briefing about the U.S. nuclear target list in February 1961, shortly after he became secretary of defense. McNamara was curious to compare the targeting-system criteria to a target known to have been destroyed, Hiroshima, burned out by a mass fire after a fifteen-kiloton bomb, Little Boy, exploded 1,900 feet above the city center on 6 August 194. This dialogue ensured:

Q. — McNamara — Have you applied your proceedures to Hiroshima?
A. — Smith — Yes. 3 DGZs of 80 KT each.

That is, were Hiroshima still a target, the JSTPS would have identified three designated ground zeros within the city and would have assigned three nuclear weapons, each equivalent to eighty kilotons of TNT, to destroy them.

This particular exchange is in a memorandum dug up by my friend, Bill Burr, and the invaluable National Security Archive.

You can read the full text of the Memorandum for the Record, ‘Secretary McNamara’s Visit to the JSTPS, 4 February 1961’, 6 February 1961, which is part of The Creation of SIOP-62, More Evidence on the Origins of Overkill, National Security Archive Electronic Briefing Book No. 130, edited by William Burr, July 13, 2004.

While you are there, you can also read the newly posted New Evidence on the Origins of Overkill, First Substantive Release of Early SIOP Histories, National Security Archive Electronic Briefing Book No. 236, edited by William Burr, November 22, 2007.


  1. MarkoB (History)

    Also P83 with reference to your thesis on China’s ASAT test is interesting. I think the same might apply to India’s DRDO and strategic policy…maybe arms control theory needs to be re-looked at…instead of controlling weapons we need to control the underlying technological complex that works on weapons innovation and production which has the militarisation of science at its core.

  2. Alex W. (History)

    Re: Hiroshima — hey, SOME people still survived, after all! Can’t be having that, can we?

  3. Yale Simkin (History)

    Ted Taylor struggled thoughout his adult life with an unwanted addiction to nuclear weapons.

    He described the day in 1950 when his daughter was born:

    “Instead of being with my wife, Caro, I had spent the day at a military intelligence office, poring over aerial photographs of Moscow, placing the sharp point of a compass in Red Square and drawing circles corresponding to distances at which moderate and severe damage would result from the explosion at different heights of a 500-kiloton made-in-America bomb. I remember feeling disappointed because none of the circles included all of Moscow.”

  4. mark F (History)


    What can you say about a person who can think that way? Just another (diss)assembly line.

  5. spacemanafrica

    Well, to be fair we are talking about a hypothetically credible countervalue strike which has to be backed up by reliable destruction of 99% of the target city. You can even go play around with some nuclear detonation simulators online and see how that’s not an unreasonable kilotonnage when the objective is the total obliteration of a population center.

    I can’t really work out the logic in using fewer or less powerful nuclear weapons in a strike on a city like Hiroshima in the early 60’s and maybe I don’t fully understand the argument against overkill. But when you’ve reached the point where you’re using any nuclear force against a metropolis you really should commit, fully. What I am saying is I wouldn’t agree with a demonstration for effect. Using nuclear weapons on civilians is worthless in half-measures, any president of ours who would use them lightly (in any sense) shouldn’t have his finger on the button.

  6. David Clark (History)

    Also keep in mind that just because you have 3 dgzs doesn’t mean you’re going to get three explosions. If your delivery system is an ICBM with, say, a 75% unpregenerated reliability, there’s only a 42% chance that you’ll get three hits, and there’s still almost a 2% chance the city will be unscathed.

    With gravity bombs, the situation is even worse (or better for the city, I guess). I can’t find my Dropshot book, but I remember survival rates for bombers being very low in that one – 40% or so. With that, the chances of three hits are only 6%, and the city has a 1 in 5 chance of surviving.

    Redundant targeting is done for reasons other than overkill.