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.