The anti-war crowd exhibits a Stalinism: a disposition to psychopathic callousness to the suffering of innocents whenever compassion would hamper the leftist agenda. I just asked a lefty colleague about the Iraqis who are happy to be liberated. He denied these reports and shrugged the idea off. I repeat:
Knocking out Saddam's regime makes innocent people in the region safer, even taking into account the short-term dangers of the invasion. This is because the regime will kill many more, if it is allowed to continue into the indefinite future, than will be killed by the invasion. (Gulf War 1991 civilian deaths: less than 3,000; Saddam kills 3,500 per month.) There is therefore no grounds to protest the invasion. There isn't even a remotely plausible case that it is wrong. The anti-war protesters are motivated by dogma, hatred, envy and stupidity. (We may psychologize when our opponent in dispute lacks any plausible argument whatsoever. He must hold his position for reasons other than argument: psychological reasons.)
"But the U.S. doesn't take out many other evil regimes in the world." This is a red herring. It is permissible to destroy those regimes, too. At best you could say that the U.S. is remiss in not doing so. But this wouldn't have the slightest tendency to show that it shouldn't knock out the Iraqi regime.
"But the U.S. has self-interested motives: to dissarm Saddam/steal oil/take over the world." Red herring. The rightness of an action is independent of its motives.
"Ah, but, you see, the U.S. does intend to take over the world, and taking over Iraq is a step in that direction." Like Afghanistan and Bosnia, I guess. This is tin-foil hat stuff. This is genuine delusional mental illness caused by hatred.
"But it's against international law." False, but even if true, irrelevant. If an action would otherwise be morally permissible, the fact that it is illegal hasn't even the slightest tendency to override and show that it is wrong. And in this case, international law is a joke because there is no international government. "But it's illegal" is a moral reason only when the action in question would contribute to anarchy. But there already is anarchy in the international sphere.
"But then any country will be able to invade any other country, now that they know UN approval isn't necessary." This is loopy. Is there any evidence that the U.S.'s disposition to punish aggressors will encourage aggressors? Even very, very stupid aggressors, who say, "Well, the U.S. gets to invade people, so we do, too."? The idea that bad regimes will be encouraged to invade decent countries is bizarre and there is not the slightest bit of evidence for it. Moreover, if the U.S.'s actions encourage decent countries to take out evil regimes, then that's good, not bad.