The conventional wisdom among U.S. grand strategists is that U.S. hegemony is exceptional—that the United States need not worry about other states engaging in counterhegemonic balancing against it. The case for U.S. hegemonic exceptionalism, however, is weak. Contrary to the predictions of Waltzian balance of power theorists, no new great powers have emerged since the end of the Cold War to restore equilibrium to the balance of power by engaging in hard balancing against the United States—that is, at least, not yet. This has led primacists to conclude that there has been no balancing against the United States. Here, however, they conflate the absence of a new distribution of power in the international political system with the absence of balancing behavior by the major second-tier powers. Moreover, the primacists' focus on the failure of new great powers to emerge, and the absence of traditional “hard” (i.e., military) counterbalancing, distracts attention from other forms of counterbalancing—notably “leash-slipping”—by major second-tier states that ultimately could lead to the same result: the end of unipolarity. Because unipolarity is the foundation of U.S. hegemony, if it ends, so too will U.S. primacy.