Americans are the most risk-aversive people on the planet - freaking out to the extent that they'll pay huge sums to cover even a one day gap in insurance coverage.
And while, for the most part, we're soft, socialist cowards, our special forces and hard core military are not.
Try an experiment and put four of five frogs in a blender, then hit the 'Puree' button. I imagine that's just about what will happen to what's left of Al Queda if another major attack happens on US soil.