In April 1993, President Lee Teng-hui of Taiwan announced his bid to join the United Nations, the “participate in the U.N.” policy. In this paper I explain why Lee launched this policy and how it was formulated. Contrary to the structural realists' claim that state actions are steered by the structure of the international system, I argue that the momentum of the “participate in the U.N.” policy lay in Taiwanese domestic politics. More specifically, the policy was mainly a product of Taiwan's party politics, while its formulation was closely associated with the internal politics of the ruling Kuomintang (KMT).