The WMD reports were obviously false at the time and the people peddling those lies clearly understood what they were doing. That wasn't a case of something being missed in the heat of the moment and discovered later - tens of millions of people took to the streets in protest and all of them were making it VERY clear that they knew the WMD story wasn't true right at the time it was first brought up.

The WMD story was clear, wilful duplicity and nothing more.