Fox reported that he wanted to resign before the 9.11 hearings but stayed on to see it through. It was also speculated that because he'd told W that the WMD issues was a "slam dunk", he's lost his credibility.
I'll never forget that Powell demanded Tenet accompany him to the UN when he made his case there. He must have known something was fishy. Powell made him sit right behind him there. Smart move on Powell's part.
Then have Tenet say the no WMD issue is his fault publicly. That's what would be helpful.