That's a lot of resources that will forever be dedicated trying to step on "cockroaches" in the kitchen.
Or you can go to war against "Nazi Germany" and rid the world of any substantial Nazi movement. We still face a threat from Communist governments, but not from Nazi governments. Let's not make that mistake again. This is a political ideology with supremacist beliefs.
We are not the first generation to deal with this threat. It has existed for hundreds of years and is making the biggest stab to conquering Europe that has been made a very long time. This is no "aberrant" cult; it is a strain of the ideology that persists. We have to get that belief system (not "Islam" but militant supremacist Islam that seeks world domination) universally rejected.
A lot of regimes have to come down for that to pass. No amount of law enforcement will change that.
How many "lone nut" terrorists are within John Kerry's "acceptable nuisance level"?
This unfortunately is the same argument that James Fallows makes in the current Atlantic. Basically declare victory in the war on terror and accept the nuisance attacks because in his view alQueda is no longer capable of successfully launching a 9/11 style attack. For which he does credit Bush's war on terror. But he sees the Long War as unacceptable and feels that we can legitimately declare it over and we the victors.