The debate on missile defense in the United States is sorely lacking in substance and has been overly politicized, especially recently given the hyper-partisan relationship between Congressional Republicans and President Obama. There is little discussion on the actual capabilities of current missile defense systems and the projected capabilities of future ones. We also haven’t paid enough attention to how others will react to a new strategic environment in which the United States has robust missile defense capabilities (or is perceived to). On the issue of European missile defense, the United States has been open about its intentions and has shown a willingness to accommodate Russian concerns, as paranoid and politically driven as they may be. Contrary to the claims of some Republicans, this isn’t capitulation in the face of Russian demands, but an attempt to balance the competing interests of US-Russian relations and missile defense. On the issue of East Asian missile defense, there has been no such dialogue with China. The United States recently announced a major expansion of its missile defense capabilities in East Asia, which it says is intended to counter the limited missile threat posed by North Korea. But those same systems, if they work as intended—which hasn’t been fully demonstrated yet—could pose a threat to China’s strategic deterrent, forcing them to upgrade and significantly expand their arsenal. This would be bad for both the U.S.-China relationship and for global security in general. China currently has 55-65 ICBMs, a far smaller number than the United States and Russia. While Russian concerns about the viability of their second-strike capability are irrational given the size of their nuclear arsenal, Chinese concerns are more grounded in reality. As the United States seeks to improve its regional and strategic defensive capabilities against North Korea, it must seek to engage with China through dialogue and information sharing about capabilities and intentions. Every effort must be made to prevent a large scale increase in the Chinese nuclear arsenal. Such an increase would weaken the Nuclear Nonproliferation Treaty, discourage reductions by other nuclear powers and weaken global nonproliferation efforts. The United States should pursue a robust diplomatic track with China on missile defense and strategic stability. While diplomacy has so far failed to break the impasse with Russia, it might have better results with China. Some of the issues worth discussing in such a dialogue have been outlined in Li Bin’s excellent new piece on this subject. Preventing a costly arms race, in both the nuclear and conventional realms, would make for a more stable US-China relationship and a more secure world.