Taiwan remains an important potential flashpoint between China and the United States. Given the geographic distance between the United States and Taiwan and the military challenge of defeating a major attack by China, an accurate assessment of Taiwan's ability to sustain a defense can be a critical factor for U.S. decisionmakers and planners. In this report, the authors develop a framework for assessing a country's capacity to resist a large-scale military attack. In that framework, a country's ability to withstand such an attack depends on four variables: political leadership and social cohesion, military effectiveness, durability, and military intervention by an ally. The authors then use that framework to assess Taiwan's capacity to resist an attack by China for 90 days — a posited minimum amount of time required for the United States to marshal sufficient forces to carry out a major combat intervention in East Asia. An accurate assessment of Taiwan's ability to withstand a large-scale attack by China could help U.S. decisionmakers and planners better anticipate and respond in such a situation.