Regardless of who would be seen as responsible, Saddam would have been toast. He wanted to survive, thus he decided not to use WMDs. Well, that's one theory anyway...
The problem is that nobody but Saddam knows what he was thinking, or if he was thinking at all. We can only judge his actions against our experience and sense of reason. To me, his actions were pretty suspicious, and I don't even have access to all the intelligence data that the US president has.