Several articles note that Bill Clinton is offering campaign advice behind the scenes for the Obama campaign and fundraising for the President.
http://www.politico.com/news/stories/0412/75452.htmlhttp://politicalticker.blogs.cnn.com/2012/04/28/bill-clinton-to-appear-at-fund-raiser-with-obama-on-sunday/http://www.washingtonpost.com/politics/once-rivals-obama-and-clintons-forge-genuine-partnership-incentive-for-both-to-make-it-work/2012/04/29/gIQAb2wNqT_story_1.htmlCould these political chits eventually lead to an Obama endorsement of Hillary? If Biden runs, then the answer is probably no. But if Biden stays out, then I think it is very possible. And having the backing of the two most recent Presidents of her party would make Hillary extremely difficult to defeat within the context of a Democratic Primary.