Picture the police chief of Dearborn. Let's say this person has a prejudice against Middle Eastern people. Obviously I am making this up - it could be the opposite for all I know. So the police chief of Dearborn, after 9/11, takes a look at which way the wind is blowing in terms of the law being whatever you can get away with with there being no political appetite for accountability against you for doing it, either from DAs and inspector-general types, or in terms of the outrage of the voters against, say, Schumer and Feinstein for going after Gonzales. In terms of both those things, the bigoted police chief who has to police a bunch of slumlike neighborhoods around Dearborn populated largely by Arab/Muslim people, may rub his hands together and say, oh boy, my job just got a lot easier. Because the climate is going to allow me to get away with a lot more accidental false positives, deliberate false positives and somewhere-in-between false positives, in the course of doing my job.
The same happens after the Christmas Day incident.
The same happens after the Times Square incident.
Law enforcement is self-interested and will sell out the Bill of Rights if it gives them "more tools."