There were reports coming from Intel that landed on both sides. That would create a problematic environment if that were the only intel we were dealing with. Most of that that I remember were challenges to some of the more widely held "smoking guns"...such as the aluminum tubes and the "secret meeting" in eastern europe.
However, we still had the UK intel, the Russian intel, and years of active subtrefuge of UN agreements...which now appear as more likely the root cause being Saddam funneling cash in the billions into his own coffers...but definitely giving credence to our and our allies claims that he was hiding something. We assumed it was WMD. Well..you know what they say about those that assume.