This may end up as the path Bloomberg/Hagel take.
If Bloomberg spends $billion it is possible he could win
As I've been saying for a while, Bloomberg and Hagel can't run on Unity08 together, right now. The rules don't allow two people from the same party to be on the ticket, so I'm guessing that one of them will become an independent.
Bloomberg might switch back to being a Democrat. As some of you might know, Bloomberg changed his party affiliation to run for mayor solely because he stood no chance in the Democratic primary.
I really don't think Bloomberg will switch back. Part of his appeal is that he is a liberal Republican and not a Democrat. If he switches to Democrat, then he'll lost a ton of liberal Republican votes, especially in the Northeast.
If they run, Bloomberg will be at the top of the ticket. He's simply not willing to be VP. And, he'll stay Republican.
Hagel will continue to blast Bush on Iraq. He'll announce that he's not running for Senate in fall of 2007. Then he'll be able to distance himself even more from the President. He say something like "The Republican Party has left." and "I don't think the current Republicans have the audacity to fix America's big problems." He'll then switch to an Independent, but probably still caucus with the Republicans. This will enable Bloomberg/Hagel to get the Unity08 endorsement.