anti-ballistic missile systems

GWB just said in his press conference this morning that he thinks there was a "reasonable" chance of shooting down that long-range Korean missile the other day. The question was about missile defense systems, with the implication that the system is what would intercept the missile. I think this is false. The missile defense system has, to public knowledge at least, not passed any of its tests without knowing where to aim a priori. Shooting down a missile with a missile is like stopping a bullet with a bullet (or an arrow with an arrow, or whatever you like); it's pretty hard. So when people say things like "missile shield" you should instead think defending yourself by shooting at the bullets heading for you. A shield not does that make.