Bin Laden says, "Kerry can't protect you, Bush can't protect you...only you can protect yourselves" Basically he's saying, if the US voters stop electing politicians who support Israel and prop up oppressive Arab governments like the Sauds, then Arab people will stop feeling the need to attack the US. Basically, Bin Laden is trrying to evolve Al Qaeda into a political group, a la the PLO or Sinn Fein.

Also, Bin Laden is only 47, so he's not exactly about to keel over, although he does have some helath problems, and probably a bit of stress as well.