Preemption at what cost?

Bush is still committed to his misguided policy of preemption, according to the Post.

What I worry about sometimes, beyond the moral problems of preemption, is what the actual performance of the doctrine does for the effectiveness of our deterrence efforts. After all, who would believe right now that the US will invade and decapitate another country? We clearly don't have the military depth of force to have three occupations going at once, and we're unlikely to leave Iraq any time soon. I wonder if showing our teeth might have been more effective had we not revealed that we can't necessarily chew everything that we bite off.