I think Biden is going to drop himself.
This is what is going to happen.
Biden announces that he is going to have to leave the ticket for "health" reasons. This then makes the health of the canidates a very relevent topic in the news media. Of course McCains old age and previous cancer will not speak well for him on this issue and he will slip further in the polls.
At the same time a leading Obama offers the VP spot to former rival hillary clinton swinging even more support to the Democratic ticket.
At this point the dems have sealed the deal pretty much and if anything happens to Obama, they got their true second choice in office.
Obama CANNOT drop Biden, biden has to drop himself.







