Mobile arguments for war

When somebody says Saddam poses less of a threat to us than North Korea, it’s quite common to say, “What about his brutality to his own people!” Aside from the fact that that North Korea is also brutal to their own people, there the uncomfortable reality that Saddam appears to be quite willing to be even more brutal to his people should we attack. If he succeeds in immolating Baghdad in order to die like a good heathen emperor, are the “We’re doing this for the good of the Iraqi people” folks going to say “We had to destroy Baghdad in order to save it”? Or will we simply drop the arguments about the good of the Iraqi people and switch to arguments about the greater geopolitical good?

One of the things that troubles me about arguments for war, like arguments against war, is that trying to chase them down is like trying to tackle a crow. They keep flying away just when you reach one to ask it a question.