Before the WMD stories started I remember reading in the family newspaper that W's lawyers told him it would not be legal to invade Iraq without an imminent threat such as WMD. The WMD stories started shortly thereafter. Yes, there were US weapons inspectors on the ground in Iraq and they couldn't find anything other than Iraq being less than 100% cooperative. It was well known by just about everyone at the time that W's stated belief of WMD was necessary to make the invasion legal. But Saddam had it coming. After the first Gulf War, Saddam attempted to have W's daddy killed. W made sure that was a fatal mistake.
Yes you are right, I stand corrected. I do remember now that it was a few months before they finally let them in. After they had let them in they then started playing cat & mouse games with the weapons inspectors.