It is also worth remember that, while we didn't find any WMD, pretty near every country who investigated at the time, including US Democrats who voted to authorize the war, believed Saddam had WMD.
Maybe the governments of "every country" believed that, but at least here (the Netherlands) there was quit a bit of scepticism in the population. This was mostly based on the reports by UN inspector Hans Blix. Although he was unable to prove there were no WMD (due to lack of cooperation of the Iraq government) he didn't report any evidence for the existence of WMD either. I remember one of his press conferences where he let out some of his frustrations, saying that if the US had such irrefutable proof of the existence of WMD, they should share it with him.
"Security is mostly a superstition. It does not exist in nature... Life is either a daring adventure or nothing." -- Helen Keller