However, I also made a specific comment about preventive war: namely that the failure in Iraq doesn't especially vindicate the argument that preventive war is almost always wrong. It is almost always wrong, and the fact that Iraq was a preventive war was a good reason to oppose it. But the specific quagmire that we find ourselves in now has very little to do with the fact that the Iraq war was preventive.It seems to me that the answer to his question is that "the" war - that is, the one we're fighting right now, defined by its aims and effects - wouldn't have happened at all if we'd launched a military intervention against a hypothetical Iraq that posed some actual, concrete threat as opposed to just being generally unsavory. In the hypothetical case, we'd be fighting an entirely different war that would have had very different goals. Presumably those would be narrower, more specific goals that would have been fairly easy to accomplish given our tremendous military superiority.
On that last point, I'd welcome argument. Maybe I'm off base. Would the war have gone better if it hadn't been preventive? Maybe so, though everyone seems to think we would have been screwed in 1991 if we'd gone all the way to Baghdad in the Gulf War, and that wasn't a preventive war. But I'm wide open to argument on this point.
But by the same token, a preventative war is, almost by definition, a war with only vague, abstract goals. I say "almost" because in practice, though not in theory, it seems unlikely that we'd be able to articulate and stay focused on a few narrow objectives against an adversary that is dangerous only in principle. Quite to the contrary, we're much more likely to instead either 1) set goals that do not correspond to actual facts (e.g., "eliminate weapons of mass destruction") or 2) set goals that do not admit of easily-quantifiable measures of success (e.g., "establish a stable, independent democracy"). In neither case is there much chance of having a successful mission because in neither case are we likely to have accomplished our goals. In both cases, meanwhile, we're likely to flail around for something resembling a useful goal and muddle around until we settle on one.
I think that's a built-in problem with preventative wars: it's too hard to set meaningful goals, and you can't accomplish a goal that isn't well set. But once you've committed yourself to the intervention, withdrawing sans victory becomes difficult. Preventative wars will therefore, as a consequence of their preventative nature, rarely result in success and will often be prone to greater misfortune.
In so many words, then, I disagree with Kevin. I think Iraq illustrates well the difficulties a war faces just in virtue of being preventative. It illustrates lots of other things, too - the dangers of incompetent leadership, for one - but it also demonstrates the nearly-inherent dangers of preventative war qua preventative.