1. Dr. Jermone Wiesner, science advisor to President John F. Kennedy, predicted that up to twenty states could acquire nuclear weapons by the mid-1980s. See “The Bomb: From Hiroshima to …” Newsweek, 9 August 1965, 53. See also “Prospects for Further Proliferation of Nuclear Weapons,” CIA Memorandum 55–1, DCI NIO 1945 / 74, 4 September 1974. For additional discussion, see Long and Grillot, “Ideas, Beliefs, and Nuclear Policies.”
2. The four new nuclear powers are India, Pakistan, Israel, and North Korea— though Israel has never formally declared its nuclear capability. While South Africa developed the bomb, it is not included because it voluntarily disarmed and remains non-nuclear today.
3. Sagan, “Why Do States Build Nuclear Weapons?” 56.
4. “More Than 40 Countries Could Have Nuclear Weapons Know-How,” Global Security Newswire, National Journal Group (September 22, 2004).
5. For discussion of why we might expect some states that once reversed their nuclear weapons program to rethink those decisions, see Levite, “Never Say Never Again.”
6. By elites, I refer to those with decision-making authority or substantial influence over decision-making.
7. I follow Stephen Krasner in defining regimes as “principles, norms, rules, and decision-making procedures around which actor expectations converge in a given issue area.” Krasner, “Structural Causes and Regime Consequences,” 1.
8. A great deal of research is being done on strengthening constructivist methodology, including by Alastair Ian Johnston, Jeffrey Checkel, Martha Finnemore, Kathryn Sikkink, and Thomas Risse.
9. See, for example, Ogilvie-White, “Is There a Theory of Nuclear Proliferation?”; Sagan, “Why Do States Build Nuclear Weapons?”; Flank, “Exploding the Black Box”; and Chafez, “The End of the Cold War.”
10. Waltz, Theory of International Politics.
11. Mearsheimer, “False Promise,” 12.
12. Samaddar, “Thinking Proliferation Theoretically,” 440.