Bush believed that Saddam Hussein was not complying with UN Resolution 1441.

Bush felt that there were unauthorized weapons of mass destruction in Iraq.

Bush knew very well that there was no real evidence to support his WMD claims. I believe that he wanted to be known as "a tough war president". Also, his main driving force were Chaney and Rumsfeld, his VP and Defense Secretary. They both wanted this war -- remember Rumsfeld's claim "we not only know he has them (WMD) we know where they are"?

Also, the American people, deep inside, wanted revenge for the 9/11 attack, and, like most religious people, are willing to believe whatever they are told is the truth.

I was flabbergasted when I viewed on TV Colin Powell, the Secretary of State, trying to convince the UN Security Council that we had proof; i.e.,

1. Recorded telephone conversation between two Iraqi military officers whose words made no sense - could have been talking about their affairs with their superiors' wives.
2. That some trucks had been moved during the night. between suspected WMD locations.

Can you believe it? That was the only "evidence" we had.