With the announcement in 2010 that sovereignty over the South China Sea was a national interest comparable to Taiwan or Tibet, China has created a new geopolitical situation in East Asia. Although Peking would seem to expect that her neighbors, all relatively smaller than China, will accept these new claims, both initial reactions and political science theory suggest instead that a countervailing coalition will be formed to offset them. Just what Taiwan will do, however, is an important question given the island’s key strategic position, its democratic government, and its increasing connectedness with China. This essay reviews the history of American approaches to East Asian alliances, arguing that at one time Washington considered dropping ties with Tokyo in favor of Peking. Then it examines the new situation, finding the United States uneasily seeking to balance China and Taiwan likely to join in.