I would also point out that many governments that chose not to support this war - certainly, the French president, Jacques Chirac, as I recall in April of last year, referred to Iraq's possession of WMD.
Once you come up with a premise, you have to work out how it all happened. It's a bit like coming up with a spectacular roof design first. Before you can get it up there, you need to build a solid foundation and supporting structure.

