What really gets me about charges that Bush lied about Iraqi WMD isn't so much that President Clinton's administration acted on it and other leading Democrats believed it because every major intelligence agency here and abroad believed Iraq had chemical weapons.
No, the charges resurrected by the left that the war is proven unnecessary by the lack of many post-1991 chemical weapons* found in Iraq after the invasion is what annoys me.
It annoys me because before the war, they too believed what Democrat leaders who had reason to know believed--Saddam had chemical weapons.
Yet despite that agreement, they did not think even the presence of chemical weapons justified war.
Ignoring that there were lots of reasons to go to war with Saddam's Iraq (for our national interests, regional stability, enforcement of past agreements made by Iraq to disarm and prove they disarmed, and humanitarian reasons), these anti-war activists made the argument that attacking Saddam could either compel Iraq to use chemical weapons against us when otherwise he would not if left safe in his palaces; or that in the chaos of invasion, chemical weapons could get loose from Saddam's control and proliferate to terrorist groups.
So before the war the anti-war activists assumed Iraq had chemical weapons but didn't want to invade; and now they argue that lack of chemical weapons nullifies the other reasons to destroy Saddam's dangerous and evil regime.
*Note that hundreds of old munitions were found, illegal delivery systems were found, and Saddam retained raw materials that the Syria Disarmament deal of 2013 included in Syria's chemical weapons arsenal.