Given that the Chinese have demonstrated the capability to obliterate satellites in low earth orbit, what does this mean for US military capabilities?

What do we know from publicly available sources?

1. The Chinese have blown up a satelitte in low earth orbit. Low Earth Orbit being commonly defined as 200 - 2000 km above the earth.
2. In the fall of 2006 the Chinese succeeded in illuminating a US satelitte with a laser. This was known by US intelligence agencies.
3. The Project for the New American Century stated in their 2000 defense review that one important objective for the US should be the 'control of space and cyberspace'. This document has been followed extensively by the Bush administration and the military over the last 7 years. There is no reason to suspect that the US military would have slacked on 'control of space' while completing all other objectives. And in fact there is evidence to support that the US has publicly attempted to push forward with the 'control of space' objective by organizing of the US Space Corps, as a division of the US Air Force. To my knowledge this plan did not go forward publicly or directly.
   

The Chinese ASAT (Anti-Satellite Test) is having some significant consequences for the remaining satellites in orbit around earth. The aging weather satellite that they destroyed on Jan 17th, 2007 has created a debris field in orbit around the planet. The more than 647 detected pieces of junk created by the explosion now sit in low earth orbit 100 to 2200 miles above earth. Claims are being made that the amount of junk in orbit has now reached critical mass, wherein a collision between junk and something useful (like a satellite that carries your favorite tv station) is inevitable. The International Space Station does not appear to be in immediate danger of such a collision. However, a prominent fear is that the amount of junk now orbiting earth will eventually hit some old piece of abandoned equipment and create a new debris field with the subsequent explosion.

The Chinese rid space of an aging weather satelitte with a nice little fireworks display. Allegedly China used a laser to blow the little beast to tiny pieces of space junk. The shot heard round the world was likely fired from an asat system at the Xichang Space Center. The US military and intelligence agencies are acting very surprised by this test, however as Aceize noted several weeks ago, this sort of technology has been suspected to exist for some time.