Yahoo! News - U.S. to Test Its Missile Defense System

Yahoo! News - U.S. to Test Its Missile Defense System: "Critics charge the technology is neither ready nor affordable, and say it fails to address the greater threat of weapons of mass destruction brought into the country by terrorists or other means." Hmm. Obviously the technology exists and is affordable if we are deploying. And I fail to see the logic on how a "missile defense" system is to stop WMD's "brought into the country by terrorists or other means" (what other means???).