I would have said no until recently. I would have said that he believed the intel he was given and thought that to head off an even bigger crisis than 9/11 he really had to act. Wrong or right, he believed he was doing it for the safety of the nation. That's what I would have said. Because I believed that was what motivated him above all else.
Then recently the report on Saudi involvement in 9/11 was declassified and released. It was damning. The Saudis were up to their necks in funding and training the 9/11 terrorists and Bush knew it. He classified it and hid it. Then he protected them. I can no longer believe that his primary motivation was defending the nation because of that. I still don't know quite why he put Saudi Arabia ahead of the USA but he did. And once that became clear, well, the war in Iraq becomes problematic.
You see at the time W was making the case for war, he told us that he had intel that said Saddam had WMDs and that he was prepared to give them to terrorists. But he couldnt show us the intel. I was left to conclude that either he was telling the truth and the issue was urgent or he was lying and was therefore an evil warmongering bastard. I thought he was a good man so I assumed he was telling the truth and based on that judgement I supported him. Fast forward to now. Knowing what I now know about his character, I can no longer assume he was being honest about the need for the war. He has lost the benefit of the doubt. So now if someone said he started that war to engage in some nation building and it had nothing to do with protecting America from terrorism, well, I'd shrug and say "could be."
The simplest explanation is the correct one. The administration of George W. Bush was a wholly owned subsidiary of the Saudi royal family.
Which was completely unacceptable. Now we have what seems to be a rogue FBI which started or not cleaned up under Bush.