As far we know CIA analysts absolutely DID NOT believe that Iraq had a nuclear program or significant chemical weapons program. Rather, what the CIA institutionally believed was that it lacked any strong evidence to make an assertion one way or another.
The case for the Iraq War was made on the back of a single informant, an informant that most Western intelligence agencies (including Israel) believed not particularly credible. The CIA also, initially, didn't believe that informant very credible. However, Cheney & Co went hunting for evidence, dredged it up, packaged it, and sold it as a "slam dunk" to the previously incredulous Secretary of State Colin Powell and CIA Director George Tenet. It's only by dint of Tenet being Director can we say that the CIA believed the justification behind the Iraq War.
The case for the Iraq War was made on the back of a single informant, an informant that most Western intelligence agencies (including Israel) believed not particularly credible. The CIA also, initially, didn't believe that informant very credible. However, Cheney & Co went hunting for evidence, dredged it up, packaged it, and sold it as a "slam dunk" to the previously incredulous Secretary of State Colin Powell and CIA Director George Tenet. It's only by dint of Tenet being Director can we say that the CIA believed the justification behind the Iraq War.