Unfortunately your argument has no merit in it. Clearly Powell thought just as the Clinton administration did that Sadaam was contained as posed no threat just as did every other Western goverment and intellifgence agency. Then all of a sudden he started saying the opposite claiming new evidence. We now know there was no new evidence and every other Western government and intelligence agency was still right. He himself apparently said about some of his speech "I'm not saying this, this is bullsh*t". He should have said that about the whole Bush plan on invading Iraq. As it stands now his career is probably over, now his integrity has been compromised.
On a more positive note Cheney and Bush are making lots of money from Halliburton and the Carlystle Group so at least it all benefited someone.