It was very sensible, given that Iraq hid the terrorist behind the first WTC bombing, to ask Clarke to make SURE Iraq wasn't behind 9/11.
Also, in the book The New Jackals by Simon Reeve, it was noted that Iraq went on its highest state of alert with its military two weeks prior to 9/11 and Saddam sent his family into his most secure bunker where Saddam himself went and didn't emerge until mid-October.