What is the process by which norms in the international system change the behavior of states? Johnston wants to identify the working parts of the causal mechanism. But rather than emphasizing pressure from other states or changing strategic interests to explain decisions to join security regimes, Johnston focuses on the social learning that takes place when policymakers interact with representatives of other states. As hard cases to test his theory, he takes several instances of the involvement by traditionally realpolitik-oriented China in security institutions in which it gave up some military advantage. He identifies three processes of socialization -- which he dubs "mimicking," "social influence," and "persuasion" -- and tries to show how one or another of them explains Chinese participation in the UN Conference on Disarmament, the ASEAN Regional Forum, the Comprehensive Nuclear Test Ban Treaty negotiations, and negotiations on a protocol to restrict the use and transfer of land mines. Given the secretiveness of China's foreign policy decision-making, Johnston can produce little direct evidence of what motivated the decision-makers, and so he uses circumstantial evidence to rule out "materialist" (hard power) explanations for China's actions. Yet in the end, the distinction between social and material motivations seems forced, since power in the international system is multifaceted. China in the 1990s (or even now) could not solve all its security problems with military power. To be sure, working diplomats make tradeoffs between weapons systems and other forms of influence, but that does not make their calculations any less power-driven.