I don’t have any more idea than anyone else does what Mubarak meant by his speech; perhaps it was just a bargaining ploy, where the stakes are where he lives in exile and how much of the swag he and his family get to keep.
But as far as I understand the situation, the two key facts are that:
1. Whatever the Egyptian constitution says on paper, as a practical matter the President of Egypt serves at the pleasure of the military.
2. Under the Egypt-Israel peace deal, the Egyptian military is heavily funded by the U.S. Treasury. The generals really need to keep that money flowing.
So the U.S. is not at all helpless. The Administration seems to have chosen to side with (apparently overwhelmingly popular) uprising. So I’m still short Mubarak futures.