Hans Blix​' report to the United Nations provided all the evidence necessary to justify removing Saddam, even without any input from the Bush administration.
BBC News - Iraq inquiry: Former UN inspector Blix says war illegal
Hans Blix also delivered information to the United Nations that resulted in sanctions against Iraq--54 altogether, I believe, before UN action was firmed up: " UN weapons inspector Hans Blix remarked in January 2003 that "Iraq appears not to have come to a genuine acceptance—not even today—of the disarmament, which was demanded of it and which it needs to carry out to win the confidence of the world and to live in peace." Among other things he noted that 1,000 short tons (910 t) of chemical agent were unaccounted for, information on Iraq's VX nerve agent program was missing, and that "no convincing evidence" was presented for the destruction of 8,500 litres (1,900 imp gal; 2,200 US gal) of anthrax that had been declared."
Was his report was signed by him and authenticated as the truth by the UN Weapons Inspection team who found this stuff. Our troops were directed to the Kurdish villages' mass burial areas and authenticated the deaths of all those people Saddam Hussein gassed.
The man was the worst terrorist in the world in his day. Clinton and Madeline Albright backed up these allegations with our own intelligence before Bush ever became President. I read the files on Iraq in 1998 and 1999 from the State Department of Madeline Albright. The information was passed on to the Bush administration and Condoleeza Rice did her job of following the money, the munitions, and other EU authentications by checking out the facts. Saddam's case got pretty ugly, and the Secretary of State's office published and added to Mrs. Albright's info as time went on. I was very interested in Iraq, read it all. Saddam was a very, very nasty man.