When the Bush administration changed the reason for the invasion of Iraq from "WMD" to "regime change" it was one of the few times they have been honest.
The call for regime change goes back to 1992 when Scooter Libby and Paul Wolfowitz, at the direction of then Secretary of Defense Dick Cheney, created a defense document calling for the removal from power of Saddam Hussein.
In 1999 the Project for a New American Century (PNAC),
http://www.newamericancentury.org/iraqclintonletter.htm">in a letter to President Clinton, again called for regime change in Iraq. According to PNAC "the only acceptable strategy is one that eliminates the possibility that Iraq will be able to use or threaten to use weapons of mass destruction. In the near term, this means a willingness to undertake military action as diplomacy is clearly failing. In the long term, it means removing Saddam Hussein and his regime from power. That now needs to become the aim of American foreign policy."
Among the names that signed the letter to Clinton were those of Paul Wolfowitz and Donald Rumsfeld.
Paul Wolfowitz admitted that regime change was the real reason for the invasion
http://ics.leeds.ac.uk/papers/vp01.cfm?outfit=pmt&requesttimeout=500&folder=339&paper=543">in an interview with Vanity Fair in 2003. According to Wolfowitz, WMD was something they could sell to the American people, something they could understand.
"The truth is that for reasons that have a lot to do with the U.S. government bureaucracy, we settled on the one issue that everyone could agree on which was weapons of mass destruction as the core reason," Wolfowitz was quoted as saying.
Remember when Richard Clarke said that the Bush administration talked about how to use the September 11th attacks against Iraq? He knew what he was talking about. The invasion of Iraq had been planned by radical conservatives for many, many years.