It is often argued that at the root of the Taiwan question are the myriad differences in politics, ideology, identity, and economy between mainland China and Taiwan. Any prospect for its peaceful resolution, it seems, hinges on bridging those differences through economic and/or political integration. Although the Taiwan conundrum has much to do with wide-ranging cross-strait divergence, this article argues that it cannot be disconnected from one important commonality between Beijing and Taipei, namely, a cross-strait normative convergence on the Westphalian notion of state sovereignty. Encompassing an exclusionary understanding of final authority, territory, and identity, Westphalian sovereignty provides both Beijing and Taipei with a commo...