But you are ignoring what happened in France. And I highly doubt that 90% of the Muslim population that exhibit characteristic X live outside of Dearborn / New York City. Also, if I understand you correctly, you are saying that simply because they are Muslim they will exhibit characteristic X, and you are not taking into account other variables such as society and whatnot. Which would help explain why Dearborn / NYC isn't burning.
If it is only supposed to be dismantling the threat to our national security, then I think it's doing a poor job of it.
So how do you know if an individual that is being wiretapped is an 'agent of a foreign power'? Terrorists by their very nature typically aren't in the employ of a foreign government.
See
here about which parts of the Geneva Conventions were ratified by the U.S. Congress.