What is the role of nuclear weapons in world politics? The political effects of nuclear weapons were central to the study of international relations during the Cold War. However, after the collapse of the Soviet Union, many people assumed that nuclear weapons were no longer relevant. Careful thinking about nuclear deterrence ground to a halt.

Events soon reminded us that nuclear weapons did not disappear with the end of the Cold War. India and Pakistan tested nuclear weapons in 1998. The United States invaded Iraq in 2003, in part due to concerns about Saddam Hussein's nuclear ambitions. North Korea withdrew from the Non-Proliferation Treaty and joined the nuclear club, carrying out its first successful nuclear explosion in 2006. Iran recently appeared to be on the cusp of building nuclear weapons. Clearly, nuclear weapons continue to influence the contemporary international landscape in many ways. Yet the field of international relations has been unable to answer critical questions about this new nuclear era.

One of those unanswered questions is how nuclear weapons shape the dynamics of coercion in international politics. An emerging wisdom – which we call the “nuclear coercionist” school – holds that nuclear weapons provide states with tremendous political leverage. According to this view, nuclear powers have special advantages in international diplomacy. Not only are they better able to deter attacks against themselves and their allies, but they can also win crises with greater ease and extract political concessions more effectively than nonnuclear countries. Nuclear weapons, according to coercionist logic, are useful for much more than self-defense – they also help states engage in military coercion.

This book has challenged this notion. It has offered an alternative theoretical approach, nuclear skepticism theory, that better explains the role of nuclear weapons in international affairs. This perspective argues that nuclear weapons do not help states throw their weight around in world politics. The reason is that it is exceedingly difficult to make coercive nuclear threats believable. Nuclear blackmail does not work because threats to launch nuclear attacks for offensive political purposes fundamentally lack credibility.