A reader e-mailed this to me, thought it worth passing along:
"I think all this speculation about why Hillary stays in misses what she is ultimately about--making it more difficult for Obama to pick anyone but a woman for his VP--Sibelius of Kansas, maybe Napolitano of AZ, or MO’s senator; surely not herself, that would be impossible for Obama, and she knows it. Thus, it would be a sign of the feminization of the party.

Of course this is not a disinterested act of feminist statesmanship. Such a black-female ticket would prove too exotic for America and surely be defeated. But the female VP would pave the way for a female nominee in four years. It would increase that longing.

So such a move is wonderful Machiavellian statesmanship; fortune is no longer a woman; necessity is."