Atomic Assurance: The Alliance Politics of Nuclear Proliferation by Alexander Lanoszka (review)

This admirably succinct monograph makes a useful contribution to our understanding of certain policy tools the United States and the Soviet Union adopted to try to curb the spread of nuclear weapons. Nonproliferation efforts have been based in part on international institutions such as the Non-Proliferation Treaty (NPT). Analysts of a realist bent, however, have long been skeptical that such endeavors can effectively prevent proliferation. Realists view security concerns as the driving force behind nuclear weapons programs, and they argue that the only way to stop proliferation is to provide states with security guarantees that obviate their need to acquire nuclear arms. The United States, with its network of defense treaties, has been the primary source of such security guarantees, particularly through efforts to extend nuclear deterrence— or a “nuclear umbrella”—over its allies. If the assurances provided by an alliance with the United States do not do the job, then Washington can also apply coercive pressure on its allies by threatening to withdraw its protection. In recent years, Alexander Lanoszka points out, numerous studies have identified this combination of assurance and coercion managed by the United States as the primary source of nonproliferation success.

Lanoszka seeks to challenge this emerging conventional wisdom, and he does so persuasively. He examines the relationship between alliances and nuclear proliferation through a set of historical case studies. He examines in depth three key cases: West Germany, Japan, and South Korea. Lanoszka conducted archival research on each of these cases, and the primary sources he cites add nuance to existing understandings of all three. He supplements the three core cases with brief discussions of five additional cases: Great Britain, France, Norway, Australia, and Taiwan.

Lanoszka begins with the observation that alliances can be effective under some conditions but not others and advances two propositions about the circumstances under which alliances are likely to inhibit states from exploring a nuclear option. He identifies one key condition with respect to assurance and another with respect to coercion. Regarding assurances, Lanoszka argues that alliances are not automatically effective; the simple fact of signing a defense treaty with the United States does not by itself prevent proliferation. Rather, security assurances are most effective when the United States places forward-deployed conventional forces in a country or its region. This provides a valuable clue about the timing of when some states began seeking a nuclear option. Lanoszka finds that an interest in nuclear weapons was most likely to be sparked when countries came to doubt the U.S. conventional commitment. This happened in several cases after the United States announced a decision to reduce troops based in a state or its region, a step that led an ally to fear abandonment by its superpower protector.

Once a U.S. ally begins seeking a nuclear capability, Washington may have to consider applying coercive pressure to get its ally to commit to nonproliferation. Lanoszka argues, however, that the United States typically finds it difficult to generate sufficient leverage to get its allies to halt nuclear activities. When the United States is able to coerce its allies successfully, this usually does not result from threats to withdraw military support but instead arises because the ally depends on the United States economically or technologically. An ally’s vulnerability to U.S. threats to impose economic sanctions or cut off the supply of nuclear technology is the key condition forwhencoercioncanbeeffective.

Combining the arguments about assurance and coercion leads to what Lanoszka describes as his “core message” (pp. 9, 153) or main “takeaway”: “alliances are better for deterring states from engaging in nuclear proliferation-related behaviors than for compelling them to give up their nuclear weapon programs” (p. 151). That is, if the United States sets up an alliance backed by credible conventional force commitments, the security assurance this conveys can prevent a state from starting a nuclear weapons program. But once a state starts working to develop a nuclear option, it becomes much harder...