I think if Obama were to lose in November (and I don't think he will), Hillary will almost certainly run in 2016. But if he wins, I think 2016 will be a much tougher race for the Democrats.

National politics are cyclical. In four more years, it's possible that Americans will be ready for another "change." And if Hillary has the feeling that she can't win by virtue of her party affiliation, I don't think she'll run. Because I don't think she can go through losing again.