Kerry said in the debate:
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's exact quote was, "I truly am not that concerned about him. I know he is on the run."
Kerry insinuated that Bush wasn't concerned with catching him, didn't think he was importnat, and would just as soon let him go. What Bush meant, obviously, was that Laden is not a threat because he has no funds, no people, no home, etc, so it doesn't make a difference if we catch him now or later. But if we let off the pressure and stop chasing him, he could regain power.
I hate the news media for not pointing this out! Even Fox did not explain it! They just pointed out that Bush did in fact say that quote.