Why do countries build nuclear weapons? What, if anything, can the international community do to stop them? As Iran pushes dangerously close to achieving a nuclear weapons capability in the face of intense international resistance, few questions are more important for the maintenance of international peace and security. Fortunately, two recent books by established scholars astutely address these critical questions.

In Sanctions, Statecraft, and Nuclear Proliferation, Etel Solingen and a stable of experts examine the role of economic sanctions in dissuading states from pursuing nuclear weapons. Solingen's earlier work on the relationship between domestic political coalitions and nuclear proliferation (Nuclear Logics, 2007) provides a theoretical starting point that helps tie the volume together. He argues that states governed by liberalizing coalitions are less likely to pursue nuclear weapons because they do not want to jeopardize international trade and investment by adopting potentially controversial foreign policies. On the other hand, states ruled by inward-looking, nationalistic coalitions have less to lose and more to gain from going nuclear and are, therefore, more likely to seek the bomb. The edited volume picks up on this insight by examining how sanctions, both positive and negative, employed by international actors might affect the strength of certain types of domestic political coalitions and, in turn, national decisions on whether to pursue nuclear weapons. This and other hypotheses are then explored in subsequent chapters that variously employ verbal argumentation, simple quantitative analysis, and in-depth case studies in order to assess how sanctions might affect the spread of nuclear weapons.

Many of the individual chapters are superb and could stand on their own. The chapter by Arthur Stein delivers a masterful explication of economic sanctions as a tool of statecraft and is so clearly written that it could be assigned in undergraduate courses. A chapter by Celia L. Reynolds and Wilfred T. Wan provides a useful service to this volume and to subsequent scholarship by presenting a detailed list of every positive and negative sanction (more than 400 in all) that the international community has directed against Iraq, Libya, Iran, and North Korea from 1990 to 2009. Daniel Drezner outlines nine distinct causal pathways by which we might expect sanctions to result in a change of policy in the target state. And David Palkki and Shane Smith provide a fascinating discussion of the effect of sanctions on nuclear decision making in Iraq, drawing on transcripts captured by coalition forces during their invasion of Iraq in 2003 that were recently translated, including those of meetings in which Saddam Hussein himself was a participant.

While individual chapters shine, the whole is certainly greater than the sum of the parts, which should be the standard by which to judge the effectiveness of an edited volume. As the first academic work devoted to the specific question of the relationship between sanctions and nuclear proliferation, the volume makes an undeniable contribution to the field.

Scholarship on nuclear proliferation can be grouped into studies that emphasize the demand side (i.e., why states want nuclear weapons) and those that privilege the supply side (i.e., the factors that enable states to build nuclear weapons). While the Solingen volume focuses largely, but not exclusively, on the demand side, Achieving Nuclear Ambitions by Jacques Hymans drills down on the supply side. Hymans explores why some determined proliferators take so long to build nuclear weapons and why others ultimately fail in their quest. He argues that the answer can be found in variations in the ways in which nuclear programs are managed cross-nationally. Successful “big science” programs require a motivated workforce that enjoys professional autonomy, conditions, he contends, that are more commonly found in Weberian legal-rational states. On the other hand, leaders in neopatrimonial states are more likely to engage in shortsighted meddling in scientific matters, undermining the professional autonomy of the scientific workforce, and ultimately crippling nuclear weapons programs.

The plausibility of the argument is first established in brief sketches of the nuclear programs of the first five nuclear powers (United States, Soviet Union, United Kingdom, France, and China), accompanied by some crude, bivariate statistical regressions.

The empirical heart of the book, however, is a careful, paired comparison of nuclear programs in Saddam Hussein's Iraq and communist China. In brilliant detail, Hymans chronicles the many ways in which meddling by Saddam and his cronies undermined the nuclear program they were ostensibly trying to promote. For example, when Saddam's cousin, Hussein Kamel Hassan al-Majid, assumed leadership of the program in 1987, he commanded the scientific team that was to build a prototype gas-centrifuge enrichment machine, a project estimated by the scientists to take two years, in only 45 days. In an attempt to meet Kamel's impossible demands, the team turned to an immediately-available but outmoded centrifuge design and ran the machine so hard that the rotor cracked under the pressure. Many more such misguided political interventions stymied Iraq's nuclear progress and, in the end, Saddam never joined the nuclear club.

Hymans argues that China, in contrast, provided its scientific workforce with the autonomy and resources needed to conduct its nuclear work under the leadership of an “organizational genius” (p. 126), Nie Rongzhen. While Saddam's Iraq spent a decade spinning its wheels, China went from zero to mushroom cloud in a mere six years. Mao Tse-Tung's China could certainly be characterized as a neopatrimonial state, but Hymans argues that the period of China's nuclear development, the late 1950s and early 1960s, was a brief window during which China was transitioning toward a Weberian legal-rational system. Exploiting within-case variation, Hymans even shows how the amazing efficiency of the Chinese nuclear program was only upset by Mao's infrequent political interventions.

Having demonstrated his argument in these two cases, Hymans valiantly takes on the leading alternative supply-side explanation for nuclear proliferation. Scholars (e.g., Matthew Kroenig, Exporting the Bomb, 2010) argue that states that receive sensitive nuclear assistance from more advanced nuclear states are better able to build nuclear weapons than states that are not the beneficiaries of such help, and that understanding patterns of nuclear technology transfer is, therefore, critical to explaining the international spread of nuclear weapons. Hymans cleverly argues, however, that nuclear cooperation can also undermine a state's ability to build nuclear weapons by facilitating a brain drain of nuclear scientists out of the recipient state. He illustrates this argument with a discussion of Marshal Tito's Yugoslavia, describing how many of the country's best and brightest people leveraged transnational scientific ties to immigrate to Western Europe and the United States. While the logic of this countervailing argument is valid, the single case study does not and cannot begin to call into question the array of previously published quantitative and qualitative evidence demonstrating a powerful link between nuclear assistance and nuclear proliferation.

In a penultimate chapter, Hymans extends the logic of his argument to explain the development of nuclear programs in the more recent cases of Libya, Pakistan, North Korea, and Iran, before concluding with policy recommendations. Along with other advice, Hymans implores policymakers to understand that, when left to their own devices, nuclear programs in neopatrimonial states will often succumb to their own internal failings.

In short, Hymans's book makes a contribution by staking out an original theoretical position on the causes of nuclear proliferation and marshaling empirical evidence in its defense. Scholars have long understood that more capable states are better able to build nuclear weapons, and Hymans provides the useful insight that capability goes beyond mere industrial capacity to include domestic political institutions and managerial styles. In some ways, the argument parallels recent literature on military effectiveness (Stephen Biddle, Military Power, 2004), which shows that military success is not determined by the material capabilities of a state's armed forces alone but by the way in which those capabilities are employed on the battlefield. In both domains, Saddam's Iraq serves as the poster child for what not to do.

Turning to a comparison of the reviewed works, it is interesting to note the divergent ways in which the two books treat the same case material. In the Solingen volume, the authors seek to understand how positive inducements, comprehensive and targeted economic sanctions, and threats of military force influenced Saddam's decision to abandon his nuclear program after the 1991 Gulf War. Hymans argues, however, that this outcome can be understood as the direct result of Iraqi mismanagement: “After 10 years and a billion dollars spent for a few grams of low-enriched uranium, [Iraq's leaders] had quite reasonably concluded that the project was essentially dead already” (p. 118).

These different perspectives raise a larger question about whether the international community can have a significant influence in shaping proliferation decisions in other countries, or if our nonproliferation policies are conducted largely in vain. Hymans places causal weight on developments in the nuclearizing state and admonishes US officials “to come to grips with the reality that this story isn't about us” (p. 267). Contrarily, authors in the edited volume, while realistic about the limits of international influence, are generally united in the belief that packages of carrots and sticks can influence the behavior of proliferant states. In actuality, a variety of both domestic and international factors probably matter, which points to a limitation in both books' research designs.

Scholars have long recognized that nuclear proliferation is a mutlicausal and probabilistic phenomenon, which makes statistical analysis a useful tool for understanding its determinants. Neither book, however, employs multivariate statistical regression, making it difficult to disentangle the appropriate causal weight to assign to the authors' highlighted variables relative to other known correlates of proliferation, such as security environment, industrial capacity, and nuclear assistance. This is a shortcoming of the literature under review, but also an opportunity for future scholars to incorporate better measures of sanctions and regime type into their statistical tests.

Nonetheless, in the originality of the positions they advance and the robust qualitative analysis they provide, both books make an important contribution to the scholarly literature and are must-reads for serious students of nuclear proliferation.