We are now what Britain was during the American Revolutionary War. Our defenses thusfar have been built with the notion that our enemies will obey the "rules of engagement". This is as flawed now as was the King's Army's philosophy some 200 years ago. The Brits expected the colonists to obey the rules of the game and were virtually helpless to the guerilla tactics the colonists employed.
We like to think we are more sophisticated, and perhaps we are. But we will forever be vulnerable to this kind of cowardly act as long as we continue to make responses that are "considered, measured and appropriate." Know why no one tried hijacking an Aeroflot airplane out of the Soviet Union? Think there weren't people who desperately wanted out of there? Of course there were and the reason they didn't was that Soviet policy was to shoot the airliner down if it tried to leave Soviet airspace.
The mongrels responsible for yesterday's activities are among the most dangerous one can encounter: religious zealots. You can no more convince them that their actions are counter-productive to their cause than you can convince them that their religious beliefs are invalid. One thing Dubya said last night really gave me some heart. As best I can recall it went, "we will not distinguish between those responsible for these attacks and the countries that give them safe harbor." I hope he can stick with that. I say, retaliate swiftly and ferociously. For openers, reduce Afghanistan to rubble and then bounce the rubble around a dozen times or so. They admit they are protecting bin Laden and even if he isn't responsible this time, he sure as hell congratulated those who were.