I really wish people would stop with obvious red herrings.
At the time of this invasion, intel agencies across the globe, including US and British, among others, had concluded that Iraq was running a wmd program.
This info was presented to Congressional Committees in both houses, and the President, who all decided to agree to what the US did.
In addition, Iraq was in gross violation of its' cease fire agreement, numerous UN resolutions, countless warnings, and firing on no fly zone aircraft.
The reality was that the no fly zone could not be maintained indefinitely, and there was no sign that Iraq would ever agree to abide by the ceasefire.
Folks on both sides of the isle agreed to that situation, and we got the vote we got to authorize force.