Matthew at Froggy Ruminations surmises that Osama bin Laden has long shuffled of his mortal coil (of course, with a little help from *our* friends).
The critical points:
1. The Bush Administration *knows* that OBL is dead.
2. President Bush won’t publicly state that it is so, even if it costs him the election.
3. Why he won’t (priorities, you know).
4. Senator Kerry knows it as well.
Kerry is a smart guy too, and he realizes what is going on. But it hasn't stopped him from trying to bait the President into abandoning a critical propaganda victory in the GWOT by incessantly peddling his Tora Bora "outsourcing" charge in all three debates. He knows that the President will not respond to this charge so he is free to make it.
As the almighty Allah once hilariously stated, OBL is a bigger fame-whore than Madonna. Mr. bin Laden, he dead. If nothing else, he died from kidney failure due to lack of access to dialysis (he was reputed to have some sort of kidney disease). Being on the run will do that. Whatever works.

