What causes nuclear
proliferation?
1
What role do security threats play in driving states to acquire
nuclear weapons? Intuitively, security is the most important factor driving nu
-
clear acquisition.
2
Yet existing security theories of proliferation, while account
-
ing for why some states with grave security concerns have developed nuclear
weapons, are unable to explain why others have not.
3
Today only nine states
have the bomb, a number much lower than the pessimistic predictions made by
Nuno P. Monteiro and Alexandre Debs are Assistant Professors of Political Science at Yale University. They
contributed equally to this article.
For comments and suggestions, the authors thank James Fearon, Frank Gavin, Matthew Kocher,
Christine Leah, Carlo Patti, Or Rabinowitz, Bruce Russett, and Scott Sagan; workshop participants
at George Washington University, Harvard University, McGill University, Princeton University,
Stanford University, the University of São Paulo, the University of Virginia, and participants in
the 2013 Princeton “Conference on Theoretical and Quantitative International Relations,” the
2013 International Studies Association annual meeting, and the 2013 SHAFR Summer Institute on
the International History of Nuclear Weapons; and the anonymous reviewers. For excellent re-
search assistance, they thank Nicholas Anderson, Gabriel Botelho, Elisabeth Cheek, Alexander Ely,
Connor Huff, Matthew Kim, Bonny Lin, William Nomikos, Chad Peltier, Teodoro Soares, and
David Tidmarsh. Alexandre Debs thanks the Center for International Security and Cooperation at
Stanford and the Berkeley Center for Political Economy at the University of California, Berkeley,
for their hospitality.
1. We deªne “nuclear proliferation” as the acquisition of nuclear weapons by a nonnuclear state,
and “nuclear forbearance” as the decision by a state to abandon its nuclear ambitions prior to nu
-
clear acquisition. We call a state’s decision to discard its existing nuclear arsenal—as South Africa
did in the early 1990s—“nuclear reversal.”
2. We deªne “security” broadly to encompass any aims that may require the use of force against
other states. On security explanations of proliferation, see William Epstein, “Why States Go—and
Don’t Go—Nuclear,” Annals of the American Academy of Political and Social Science, Vol. 430, No. 1
(March 1977), pp. 18–28; Richard K. Betts, “Paranoids, Pygmies, Pariahs, and Nonproliferation,”
Foreign Policy, Spring 1977, pp. 157–183; Stephen M. Meyer, The Dynamics of Nuclear Proliferation
(Chicago: University of Chicago Press, 1986); John J. Mearsheimer, “Back to the Future: Instability
in Europe after the Cold War,” International Security, Vol. 15, No. 4 (Summer 1990), pp. 5–56;
Benjamin Frankel, “The Brooding Shadow: Systemic Incentives and Nuclear Weapons Prolifera
-
tion,” Security Studies, Vol. 2, Nos. 3–4 (Spring/Summer 1993), pp. 37–78; and Bradley A. Thayer,
“The Causes of Nuclear Proliferation and the Utility of the Nuclear Non-Proliferation Regime,” Se
-
curity Studies, Vol. 4, No. 3 (Spring 1995), pp. 463–519. For an early literature review, see Scott D.
Sagan, “Why Do States Build Nuclear Weapons? Three Models in Search of a Bomb,” International
Security, Vol. 21, No. 3 (Winter 1996/97), pp. 54–86, at p. 85.
3. See T.V. Paul, Power versus Prudence: Why Nations Forgo Nuclear Weapons (Montreal: McGill-
Queen’s University Press, 2000). Paul’s view is unable to account for variation in the nuclear status
of states facing serious security threats.
The Strategic Logic of Nuclear Proliferation
The Strategic Logic of
Nuclear Proliferation
Nuno P. Monteiro
and
Alexandre Debs
International Security, Vol. 39, No. 2 (Fall 2014), pp. 7–51, doi:10.1162/ISEC_a_00177
© 2014 by the President and Fellows of Harvard College and the Massachusetts Institute of Technology.
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