Why did Bush want to invade Iraq?

It was a long term conservative goal. Conservatives were angry that Bush stopped the Persian Gulf War without going on the Baghdad and removing Saddam. One part, as I remember, was that the Iraq war was partly considered by the conservatives as an antidote to "The Vietnam Syndrome" that kept America from using its military power to enforce its international decrees.

In a larger sense, the entire conservative movement seems to be an emotional counter-revolution to the civil rights movement, the Vietnam anti-war movement and Watergate. They feel that Nixon was treated badly, purely for political reasons. The conservative movement is fed and supported by the fundamentalist so-called Christians who are also reacting to a century of social change, but the key players in the administration are all pro-Nixon, pro-Vietnam War, and Pro-"Joe McCarthy", anti-union and anti-civil rights.

The Bush administration and the conservative movement in general is a reaction against the changes in America since WW I.

The war in Iraq was to have been the proof that all the social changes the conservatives oppose have been wrong.

Instead, the Iraq War is becoming proof that the Conservatives are unAmerican and very, very wrong. The more they attempt to act, the more they prove how unAmerican and wrong they are.