There will be no second act for Hillary Clinton in her quest to become President. This is her only chance. And now her hopes rest on Barack Obama in 2 conflicting ways. First Hillary needs Obama to choose her as the Vice Presidential nominee. Next, Hillary needs the Obama-Clinton ticket to lose in November.
That's right, if Hillary ever wants to become President, she needs to get on the ticket, and then have it lose.
If Obama wins with/without Hillary on the ticket, he will run again for re-election, and then win/lose, anyone associated with him and the administration will be political roadkill. There is no way for Obama to leave Washington with coattails for a VP.
If Hillary is not the VP nominee, and Obama loses, she will get the blame somehow, someway from the black community. That will make another run impossible. People aren't rational at all times, and many in the black community aren't rational much of the time when the topic is race and relations. Since Hillary will be perceived as benefitting from an Obama loss, the logic will be twisted to say she harmed him in a covert way. If there is any kind of incident with Bill Clinton or Hillary that can be spun to place blame on them for an Obama loss it will be done. In the event there isn't any evidence it will be fabricated.
The one small chance is that everyone is completely sold on the Clintons' desire to be VP, and how they've become 1 with the Obama destiny. Then dramatically, wait for the right-wing to torpedo Obama personally. It needs to be so connected to the right-wing that the Clintons couldn't possibly be involved somehow. If they are on the ticket, and have totally sold out to win then Hillary will survive as Obama's heir.
Realistically, Obama must have at least a 80% chance to win this election. But unfortunately a person more qualified and a great leader is finished in national politics.