evidence: U.S. air bases. From a handful of conventionally armed ballistic missiles in 1996, China's inventory now numbers roughly 1,400 ballistic missiles and hundreds of cruise missiles. Although most are short-range systems, they include a growing number of intermediate-range ballistic missiles that can reach U.S. bases in Japan. Importantly, accuracy has also improved. Circular error probabilities have decreased from hundreds of meters in the 1990s to as little as five or ten meters today. Weapon ranges have increased from short (less than 1,000 km) to medium (1,000–3,000 km). [...] This larger and more varied inventory of precision and standoff weapons enables U.S. air forces to attack more targets and cause more damage with each attack. To assess the net impact of improvements to both U.S. offensive and Chinese defensive capabilities, we modeled attacks on the 40 Chinese air bases within unrefueled fighter range of Taiwan, and, separately, on the smaller number from which Chinese aircraft could range the Spratly Islands. Runway attack models suggest that, in 1996, U.S. air attacks could close Chinese runways for an average of eight hours. This figure had increased to between two and three days by 2010, and it remained roughly similar through 2017. In all four snapshot years, U.S. air forces could effectively close all of China's air bases opposite the Spratly Islands for the first week of operations. While ground attack represents a rare bright spot for relative U.S. performance, it is important to note that the inventory of standoff weapons is finite, and performance in a longer conflict would depend on a wider range of factors.