The reportedly successful test of a Chinese anti-missile system should give US planners at DOD, Foggy Bottom, and the White House pause.

While Chinese statements did not provide much detail, unofficial Chinese reporting strongly imply that this test involved a Hongqi (Red Flag)-9 missile. Other unofficial Chinese news sources report that the test involved intercepting a ballistic target at an altitude above 20000 meters. This, according to a Global Times (Huanqiu Shibao) report, made the interceptor better than a Patriot PAC-3.

Much as China tested an anti-satellite system even as its diplomats claimed that China was not interested in “militarizing space,” it would seem that Chinese concerns about US missile defense developments are more a reflection of concerns about being outpaced by American technological capability than foregoing a capability. Moreover, like the ASAT test, the anti-missile test reflects a steady, ongoing program that has reached a development milestone suitable for testing systems.

What should be of concern, however, isn’t simply that China is developing anti-missile capabilities. Indeed, only the incredibly naïve would have believed that China wasn’t interested in developing such capabilities itself. Rather, it is what China is likely to do with such a capability, once it has reached operational status. Whether aimed at India and Russia, or as part of a long-term anti-ICBM capability aimed at the United States, a China that is defended by an anti-missile system is one that would pose an even greater challenge to the United States.

But this is where a potential diplomatic opportunity for the U.S. presents itself. A missile defense system in the hands of the Chinese is not a challenge to the U.S. if the Chinese pursue it in the context of adopting a genuinely defensive strategic posture—a posture that is not threatening either their neighbors, U.S. friends (including Taiwan) and allies, or the U.S. itself. As such, the U.S. should make it clear that it will not object to the development and deployment of missile defense systems by China if China also adopts this broader defensive, non-threatening posture. It might signal this through, for example, a reduction in the number of missiles aimed at Taiwan (as proposed by President Ma Ying-jeou).

On the other hand, Chinese interest in anti-missile systems should give pause to the Administration’s efforts at eliminating global nuclear arms, because the Chinese continue to pursue a nuclear modernization program. If such a goal were to be seriously pursued, then at some point, the level of U.S. nuclear forces would decline to such an extent that even a moderately effective anti-missile system could seriously affect deterrence and advance China’s position to threaten others. Beijing, it would seem, is responding in deeds to the President’s words.

It looks like 2010 will be “interesting times” for the Obama administration.