That is obviously where the expenditure of resources in prevention is best used. It is eminently reasonable to stop new immigration from suspect countries -- and doing so will not unduly strain our resources for fighting this battle.
But I must say that some of the wild claims of 600-900k enemies in our midst ready to strike is laughable. How many army divisions do these people want to use rounding up and transporting these suspects? Chasing these phantoms will greatly impact our ability to take the fight to enemy shores -- where the fight will do the most good. Osama would be laughing himself silly thinking of us spending so much effort to yield no significant result.
Let's sit back just for a minute and examine the facts: In the six weeks since 9/11, all of the "massive numbers" of terrorist minions in our midst have managed to kill one (1) American. ONE. And this occuring while we are attacking with significant success their primary base of operations -- and hunting down their leaders in their homes. I would think that they wouldn't want to take that sitting down, if they could actually do anything about it. Obviously, they can't.
"Never underestimate your enemy" is an old, well-used line; if some of the advice I see here were actually followed, we would hamstring our efforts by over-estimating our enemy.
You don't have to go far to find them. Go to many mosques in Brooklyn, Detroit and elswhere and you will find overt calls for jihad.
Those buggers are waiting for a signal. They generally like to wait a while for things to cool down.
CALL YOUR CONGRESSMAN AND DEMAND MORATORIUM ON IMMIGRATION AND VISITS FROM THE MIDDLE EAST!!