Jay Bullock calls. I'm not going to award the hand because it depends on what the meaning of the word "tied" is. There is a difference between what Peter is saying, i.e., Bush never said that Iraq was behind 9/11 and much of what Jay cites which amounts to the claim that the war in Iraq was part of the war on Terror which began - or at least was brought home - on 9/11.
Bush never did make the claim that Iraq was behind 9/11. Although there is evidence of ties between Iraq and al Qaeda, that wasn't the argument that is behind the cites that Iraq was a stage in the same war or that we invaded Iraq because we were attacked.
Shortly after 9-11, I was having a conversation with local attorney and sometimes candidate for public office, Matt Flynn. I think Matt was making the mistake of trying to sue my client and I was dishing out the required beatdown (or it could have been about something else entirely; I really don't recall). In any event, Matt said something pithy and profound - especially for a Democrat. Osama bin Laden, he said, is a metaphor.
He was right. There are 100 guys ready to emerge from the desert for every Osama. Simply tracking down and killing (or, if we are to adopt the Spielbergian mentality of Munich, administering due process to)the folks who carried out the attack doesn't end the war.
Liberals recognizing this have generally called for addressing "root causes" and Bush agreed. For the left, addressing root causes generally means giving people money or, in this case, maybe throwing Israel under the bus.
For Bush, it was doing two things. First, he wanted to change the rules of the game. He wanted to send the message that their is no longer any such thing as neutrality in the war between Islamofascist terror and modernity. Iraq may not have been involved in 9-11 or even had strong ties with al Qaeda, but they were recognized, not just by Bush, but by the Clinton administration as one of the leading state sponsors of terrorism.
Opponents of the war argue that Iraq was not the only such sponsor as if moving against one requires moving against them all. What Iraq was is a terror sponsoring state about which there were many other reasons to move, including its reign of terror against its own people and what everyone agreed was its noncompliance with the UN inspection regime. Invading Iraq, the argument went, would remove a sponsor of terror and send a shot across the Saudi's bow. Knock down our buildings and we take down two countries. Want to try again?
The other goal - which made it part of the same war - was to create a democratic regime in the middle east that might serve as a beacon for reform.
Did it work? I don't know and don't think any of us will for quite some time.