Sometimes fact-checking is a murky business, with the truth lying in the gray area between two candidates' positions. Whether Bush said he wasn't concerned about Osama Bin Laden isn't one of those situations, however.
From the debate transcript:
KERRY: Six months after he said Osama bin Laden must be caught dead or alive, this president was asked, "Where is Osama bin Laden?" He said, "I don't know. I don't really think about him very much. I'm not that concerned."
BUSH: Gosh, I just don't think I ever said I'm not worried about Osama bin Laden. It's kind of one of those exaggerations.
Q: But don't you believe that the threat that bin Laden posed won't truly be eliminated until he is found either dead or alive?
THE PRESIDENT: Well, as I say, we haven't heard much from him. And I wouldn't necessarily say he's at the center of any command structure. And, again, I don't know where he is. I -- I'll repeat what I said. I truly am not that concerned about him. I know he is on the run.