There's this attitude out there where one's foreign policy abilities are judged by whether you supported the right wars, with people like Peter Beinart checking off their little lists. The foreign policy hawks see supporting wars as courageous acts, as if sending other peoples' kids off to die and voting for massive defense budget increases requires courage instead of a healthy possession of sociopathic tendencies.
Wars are failures. A primary purpose of sensible foreign policy is to stop them. When wars happen, our foreign policy has failed. That isn't to say there's never a point when they're necessary or justified, but that point is simply an acknowledgment that the people in charge failed.
From Rosencrantz & Guildenstern are dead:
There must have been a moment, at the beginning, where we could have said -- no. But, somehow we missed it.
Well, we'll know better next time.