This article explores two starkly contrasting analytic approaches to assessing the performance of U.S. security strategy in East Asia since 1991: a positivesum approach, emphasizing the danger of security dilemmas and spirals of tension, and a zero-sum approach, emphasizing power competition and the long-term dangers posed by China's rise. In the policy world, the differences between these apparently irreconcilable perspectives are not so clear. Certain policies—for example, maintaining a strong U.S.-Japan alliance—flow from either logic. Moreover, each approach sometimes counsels counterintuitive policy prescriptions that are generally associated with the other. Relatively assertive U.S. security postures apparently have furthered positive-sum regional goals by catalyzing China to adopt reassuring policies toward its neighbors as a hedge against potential U.S. encirclement. From a zero-sum perspective, the United States often competes more effectively for regional influence by cooperating with China than it would by seeking to contain China's economic growth and diplomatic influence.