Indeed they are. One tried to kill hundreds with a car bomb in NY recently, and another murdered a bunch of soldiers at Ft Hood. Tip of an ugly iceberg.
Keep in mind that the "Patriot" Act did nothing to interdict those attempts, and even if it did, it would not be justified.
Also, our worst enemies are not trying to blow a few of us up, they are enslaving all of us and our posterity. At least, those of us that are not ripped apart in the womb.
Freegards!