Nicholas L. Miller

The Secret Success of Nonproliferation Sanctions

Building on the rationalist literature on sanctions, this article argues that economic and political sanctions are a successful tool of nonproliferation policy, but that selection effects have rendered this success largely hidden. Since the late 1970s�when the United States made the threat of sanctions credible through congressional legislation and began regularly employing sanctions against proliferating states�sanctions have been ineffective in halting ongoing nuclear weapons programs, but they have succeeded in deterring states from starting nuclear weapons programs in the first place and have thus contributed to a decline in the rate of nuclear pursuit. The logic of the argument is simple: rational leaders assess the risk of sanctions before initiating a nuclear weapons program, which produces a selection effect whereby states highly vulnerable to sanctions are deterred from starting nuclear weapons programs in the first place, so long as the threat is credible. Vulnerability is a function of a states level of economic and security dependence on the United States�states with greater dependence have more to lose from US sanctions and are more likely to be sensitive to US-sponsored norms. The end result of this selection effect is that since the late 1970s, only insulated, inward-looking regimes have pursued nuclear weapons and become the target of imposed sanctions, thus rendering the observed success rate of nonproliferation sanctions low. I find support for the argument based on statistical analysis of a global sample of countries from 1950 to 2000, an original data set of US nonproliferation sanctions episodes, and qualitative analysis of the South Korean and Taiwanese nuclear weapons programs.

Questioning the Effect of Nuclear Weapons on Conflict

We examine the effect of nuclear weapons on interstate conflict. Using more appropriate methodologies than have previously been used, we find that dyads in which both states possess nuclear weapons are not significantly less likely to fight wars, nor are they significantly more or less belligerent at low levels of conflict. This stands in contrast to previous work, which suggests nuclear dyads are some 2.7 million times less likely to fight wars. We additionally find that dyads in which one state possesses nuclear weapons are more prone to low-level conflict (but not more prone to war). This appears to be because nuclear-armed states expand their interests after nuclear acquisition rather than because nuclear weapons provide a shield behind which states can aggress against more powerful conventional-armed states. This calls into question conventional wisdom on the impact of nuclear weapons and has policy implications for the impact of nuclear proliferation.

Nuclear Dominoes: A Self-Defeating Prophecy?

Is the nuclear domino theory historically valid? Despite its longstanding centrality to thinking on nuclear proliferation amongst scholars and policymakers, in recent years a revisionist consensus has emerged in opposition to this traditional view. Based on an analysis of historical evidence from the aftermath of the 1964 Chinese nuclear test, this article argues that scholars have gone too far in rejecting the nuclear domino theory. Reactive proliferation has been more prevalent than commonly believed, and while it is true that only India acquired a nuclear arsenal in response to the Chinese test, to a significant extent this is precisely because the United States was aware of the danger of reactive proliferation and worked to stop it. Finally, the historical evidence suggests that the nuclear domino theory is compatible with both domestic and prestige motivations for proliferation in addition to the security motives normally associated with the theory.

Why Nuclear Energy Programs Rarely Lead to Proliferation

The conventional wisdom suggests that states with nuclear energy programs are more likely to seek or acquire nuclear weapons. Yet there is a dearth of systematic empirical work that directly assesses this proposition. A systematic analysis of the historical evidence suggests that the link between nuclear energy programs and proliferation is overstated. Although such programs increase the technical capacity of a state to build nuclear weapons, they have important countervailing political effects that limit the odds of proliferation. Specifically, nuclear energy programs increase the likelihood that parallel nuclear weapons programs will be detected and face counterproliferation pressures; they also increase the costliness of nonproliferation sanctions. Contrary to the conventional wisdom, states with nuclear energy programs historically have not been significantly more likely to seek or acquire nuclear weapons. A combination of qualitative and quantitative evidence supports the plausibility of the countervailing political effects of nuclear energy programs.

Red lines in nuclear nonproliferation

ABSTRACT States that seek to prevent nuclear proliferation through threats of force or sanctions often set “red lines,” which set limits on nuclear capabilities beyond which a proliferator must risk triggering a punitive response. Yet despite a wide range of possible red lines that states could choose—for example, constructing a nuclear weapon (weaponization), enriching uranium, or conducting a nuclear test—the academic literature is nearly silent on the tradeoffs inherent in selecting one of these red lines over another. Specifically, what are the vulnerabilities in each red line that proliferators can exploit to advance their nuclear program while limiting the punitive response? To address this question, this article introduces a theory of red lines and how they are challenged. We apply this theory to red lines in nuclear nonproliferation and offer historical evidence to support it.