If there is, for example, a "biological 9-11" which kills another five or ten thousand (or many more) Americans, and the trail to the killers leads through the mosques and cultural centers (again) then all bets will be off. You're right. They should just leave, and those that don't volunteer should be visited by INS and strongly encouraged to go back from whence they've come. People are showing great restraint right now, by and large...but another hit like 9-11 and all hell is likely to break loose.
Damn right it will. Have you read the new "cropduster" threads?