Daniel Drezner fails to make an important distinction. He writes:
danieldrezner.com :: Daniel W. Drezner :: Blog: [Colonel Larry] Wilkerson also points out, however, that there was a stronger pre-war consensus on Iraqi WMD intellgence than many want to believe...
"WMD" means chemical, biological, and nuclear weapons. Nearly everybody in the intelligence community was confident that Saddam Hussein had chemical and biological weapons. But there was no consensus that Saddam Hussein had nuclear weapons, or an ongoing nuclear weapons program--as indeed he did not.
Nukes are the big deal. Nukes can justify an invasion. Chemical weapons--not.