You can't win.
Bush invades Iraq on the grounds that Iraq is a threat to the free world. Some of his excuses don't pan out(ie WMD) but Hussein was a bad guy, he hated the US and her allies, he hated freedom. He supported terrorism(supposedly). The UN wouldn't do anything about it so Bush did. Look at the shit he's in now. What are his critics saying? Shouldn't have invaded. Didn't have enough reason to invade. Couldn't make an Al Queda tie. Should pull out now. Americans are dying. We don't belong there.
What if we use that same reasoning in pre 9-11 actions? What if more military action was taken before 9-11? The same people who condemn him now would have condemned him then. On one hand he's critisized for taking action and on the other hand he's critisized for not taking action.
You just can't win.