What did Kerry want Bush to apologize for when Kerry messed up his joke?

Was there something in particular that Kerry wanted Bush to apologize for that had to do with Kerry's blunder? Was it just an attempt at damage control as he knew that his die hard supporters would automatically agree with him if he demanded an apology from Bush?
Update: But why so suddenly try to force an apology about Iraq? Couldn't he do that anytime?
Update 2: Yes, I noticed that he didn't laugh or smile. I just assumed its cause he lost his place and was trying to find his way back by making stuff up on the spot.
21 answers 21