The close working relationship between Hillary Clinton and Obama during her time as his secretary of State helped heal the bruises of their knockdown contest in 2008. But they have faded rather than disappeared entirely, and they could show up livid again as the election clock begins to tick more loudly.

Hillary Clinton is more popular in polls than Obama, but her numbers have recently taken a hit. Her approval rating dropped to 46 percent in a NBC/Wall Street Journal poll released in mid-October, down from 56 percent in January. Obama’s approval rating slipped to 41 percent.

At the same time, although Team Obama appreciates Bill Clinton’s abilities as “explainer-in-chief” they are exasperated by his tendency to storm the stage at inconvenient moments.

“It’s going to be a delicate balancing act for both … camps, no doubt about it,” said Democratic strategist Jim Manley, former aide to Senate Majority Leader Harry Reid (D-Nev.). “The former president still has an ability to generate news, for better or worse, whenever he wants.”