Burden of proof is on you to prove that. Objective sources only, please.
http://www.factcheck.org/bushs_16_words_on_iraq_uranium.html
There's probably no-one truly objective on the subject, as politics are entwined in every aspect... but Clarke worked under four administrations. Tenet's book sheds light on the subject as well.
While some were truly evil, I tend to believe that Bush wanted to believe it enough that he convinced himself of it. The human mind is a subject of its own.