Today's OWH has an interesting article on an issue dear to my heart, one that I have been a long time proponent of (twenty plus years) - anti-ballistic missile defenses. I find the case for defensive weapons which can prevent the loss of an entire American (or allied) city to be a pretty convincing case for such weapons. Critics argue the cost is too high, or that the weapons can be easily fooled, defeated, or just plain won't work - in spite of several successsful tests (critics claim they are too simple, ignoring that is the way all programs start).
I would say the cost of losing a city is also pretty high, and that the technology is getting better all the time, particularly as high end computing power and sophisticated tracking radar inproves. Another point to make is that any one system is not going to be infallible, which is why the system being designed is multi-layered using several different technologies - US Navy ships, Army and USAF radars and missile interceptors, and possibly USAF aircraft and satellites. Another point is that possessing such systems terribly complicate the planning for an attack by a potential rogue state (see Iran, North Korea).
I have to applaud Senator Nelson (D-NE) for being a voice of reason on the issue - yes, the systems are expensive, but the role they can play in US defense strategy could be critical.
"Sen. Ben Nelson, D-Neb., an Armed Services Committee member, has concerns about the system's viability, but said it could play an important role."I don't want America to have a false sense of security with these defense missiles on the ground that may not actually work to knock enemy missiles out of the sky," Nelson said. "I do think a robust program is important, but we have to remember it's just one piece of the puzzle on homeland defense."