I don't know it was the thing to do to go into Iraq. History will only record the result, but even then we will never know the outcome of a different coarse of action, or inaction for that matter.
In my view however, it is imperative that we realize this is a war. A group of evangelical extremist Islamists have taken a position from a selective literal reading of the Qur'an and built it into a military and political movement. Their enemy is everyone else and particularly the West. They fight this war by targeting unsuspecting innocents and have no regard for life including their own.
Just possibly if the US had acknowledged this fact after the US embassy bombings in Africa, 9/11 could have been prevented and the enemy would be a lot weaker than they are now.
We are up against an enemy that has no borders and in fact in some cases lives among us. It is a very difficult war to fight and all we can do is hope that our leaders make the right decisions.