We broke it. We bought it.
Bush couldn't gamble on that Saddam might NOT have WMD, and that he might NOT hand them off to a terrorist group, which just MIGHT pull off an attack on US. Too many American lives at stake for him to bet against the available intelligence from CIA and all the other western nations. So he invaded.
We didn't find anything. Good. We were never at danger from this avenue. Now we need to fix what we broke.
But think about the "WHAT IF..."
Militaries around the world operate on the "what if..." principle. They anticipate the worst case scenario because anything less is insufficient.
What if a few terrorists infected with smallpox showed up at JFK in New York? We lose 5000 lives and 15000 permanantly disabled or scarred for life. What will the people say? "Bush cared about Saddam and the UN more than American lives?" "Good job, Bush, for working with our international allies to resolve the matter peacefully?" I bet the words won't be so kind.