What you really have to look out for is America`s Arogance on the whole deal. The US is trying to re-word the Treaty signed with Russia and China. At the moment any form of Missile Shield is not permitted. However, the US is trying to get a section added to allow them to create one ( In fact testing is still in a preliminary stage and hasnt been too successful yet ). China and Russia are naturally against the idea and with good reason. An active defense shield would make their technologies obsolete but allow the US to launch a missile strike if they felt the need. On a wider picture, if the US gives this technology to its Allies, i.e. South Korea as has been suggested in the past, the world could once again fall into a massive arms race. Weapons to counteract the shield system, weapons to countact the counterweapons etc...
Why not just get pissed and shout a bit. Works for me after a weeks work!