PROJECT ON MANAGING THE ATOM When Did (and Didn’t) States Proliferate? Chronicling the Spread of Nuclear Weapons Philipp C. Bleek James Martin Center for Nonproliferation Studies The Project on Managing the Atom Belfer Center for Science and International Affairs Harvard Kennedy School 79 JFK Street Cambridge, MA 02138 The author of this report invites liberal use of the information provided in it for educational purposes, requiring only that the reproduced material clearly cite the source, using: Philipp C. Bleek, “When Did (and Didn’t) States Proliferate? Chronicling the Spread of Nuclear Weapons,” Discussion Paper (Cambridge, MA: Project on Managing the Atom, Belfer Center for Science and International Affairs, Harvard Kennedy School and the James Martin Center for Nonproliferation Studies, Middlebury Institute of International Studies, Monterey, CA., June 2017). Note: This is intended to be a living document, and will be updated periodically, perhaps on an annual basis, as new information emerges. Correspondence should be sent to the author at
[email protected], if possible with the email subject line “Proliferation chronicle correspon- dence.” www.belfercenter.org/mta Cover photo: 19-kiloton Whitney shot, Operation Plumbbob, September 23, 1957, Nevada Test Site. X-rays generated by the detonation strip electrons off atoms in the air. The electrons then rejoin the atoms, producing a flash of electrical discharge that creates the feathery light seen here. Los Alamos National Laboratory, National Security Science (July 2015), p. 19, shared by Alex Wellerstein. The views expressed in this report are those of the author and do not reflect the official policies or positions of any current or past employers or funders.