Since 1945, the United States has repeatedly used the threat of military force to persuade weaker states to change their behavior. But these coercive threats have often failed; many times, the leaders of weaker states have stood fast. In this fascinating and carefully argued study, Pfundstein Chamberlain puts forward a “costly compellence theory” to explain this pattern of resistance. After examining the Cuban missile crisis, the confrontations that led to U.S. military action against Iraq in 1990 and 2003, and the 2011 conflict with Libya, she argues that the leaders of weaker states do not doubt that the United States will use force when it threatens to; they do, however, doubt its willingness to stay committed to effecting change over the long term, after the bombs have fallen. The United States was successful during the crisis over Cuba precisely because the conditions of the Cold War made its threats more “costly” to execute—and so its threats then were more convincing than they were during the post–Cold War cases. Pfundstein Chamberlain does not miss the irony of this finding: it is precisely the United States’ position as an unchallenged global hegemon that makes its coercive threats less effective.