I tried to find if someone had diaried this before, but I didn't find mention. I've been thinking about this: If it's next to impossible for Hillary to win the nomination, why is she going on? Why does she boost McCain and attack Obama?
I think the answer may be 2012.
Hillary turns 61 this October. If Obama wins the presidency, she likely will not have a good opportunity to run again until 2016. That'd make her 69 by the November election.
Now, McCain, of course, is 71, and Reagan was 69 when he was first elected. Nonetheless, it's on the high side for a first term President. So if Hillary's looking out for her interests before the country's, then if she can't win this year, she wants a shot in 2012. What's her best shot for that? President McCain.
It doesn't matter what kind of President he'd be--in fact, the worse the better. That makes it that much easier to beat him.
I actually think this makes more sense than the idea that Hillary is still fighting for this year's nomination--if she pulled off the miracle and beat Obama, would she really have much of a shot after pissing off huge swaths of Democratic voters? I don't think so.