@ CK MacLeod:
Elected leftists will support serious security measures as long as, and to the extent that, their very life as elected officials is at stake. Non-elected leftists are bound by no such concerns--they will immediately interpret new attacks as a prelude to the establishment of your American Protective Leagues, which they will proceed to fight tooth and nail before anyone has even considered anything along those lines--because they are certain that Americans are always itching to lynch them some weird looking and sounding furriners. Since, in fact, Americans have their own version of Never Again in the forms of segregation, the WWII internment camps and McCarthyism, our collective hesitation about bringing any war home is extremely powerful. It would take a lot to push us there, and by that time the Left will have had plenty of time to help the uncooperative Muslims lawyer up.
But, obviously, we'll have to see if it comes to that. My original point was that you can't possibly take cooperation for granted--I don't know how one would go about proving or disproving that, though.
@ CK MacLeod:
I would be surprised to see much cooperativeness on the part of Muslims in response to demands for higher levels of scrutiny, profiling, requests for information, etc. Such demands would themselves be easy to portray as anti-Muslim activity. And many would make it their business to thus portray them. I'm less worried about the Muslims themselves than about the Left. American Muslims, left to themselves, would be likely, for the most part, to show themselves loyal and to act reasonably in the way you describe. But it would be very difficult to pass up the role of exemplary victim that the Left would offer--those who do will be seen as both whatever the Islamic version of an "Uncle Tom" is and as as suckers, since simple self-interest will counsel individuals to hop on the bandwagon of lawsuits and demands for preferential treatment. The Left is, by now, to a great extent the collective defense attorney to the criminals, rioters and terrorists of the world, they like to gather all those who might ever be associated with criminals, rioters and terrorists into what are essentially global class action lawsuits, and they have gotten very good at it. All this will provide enormous leverage to the more uncooperative elements of the community, who will be able to hold the rest hostage.
@ CK MacLeod:
I expect the American Muslim community would, in the main, be highly cooperative.
A great deal depends upon this claim, doesn't it? And upon what would make whatever uncooperativeness might be encountered "unmain."