What is Bill Clinton up to?

Editor's note: Michael Duffy is an executive editor at Time and the co-author with Nancy Gibbs of "The Presidents Club: Inside the World's Most Exclusive Fraternity."

(CNN) -- The interesting news in the latest CNN/ORC International poll that Bill Clinton is pulling a 66% favorable rating among Americans suggests the 42nd president has the power to help or hurt Barack Obama as the 2012 campaign enters its final five months.

The question is: Which has he been doing more of lately?

The poll was a reminder that Americans tend to be more forgiving of their presidents over time, no matter how long they served, which party they hailed from or how voters may have felt about a commander in chief at the moment he stepped down.

Michael Duffy

Jimmy Carter (54%), George Herbert Walker Bush (59%) and Clinton, who have been out of office between 31 and 11 years, all earned personal approval ratings north of 50%; only George W. Bush, who stepped down three years ago, is below 50%. But even his rating has improved since he returned to private life. Being an ex-president is almost always good for your approval rating.

Photos: Secrets of the Presidents Club, from Truman to Obama

The CNN poll appears at the moment when Clinton has once again been playing an outsize role on the public stage, and many have suggested all sorts of theories and reasons for maneuvering. Some have read in his comments about Mitt Romney (he called his business record "sterling") a desire to undercut Obama or set the table for a run by his wife, Hillary, in 2016. This analysis gained momentum when Clinton told CNBC that economics demanded that the Bush tax cuts should be extended temporarily. That comment led Clinton to apologize.

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But the evidence doesn't really support a campaign of sabotage. A simpler explanation for Clinton's capering -- and one that better fits Clinton's record -- is that he is a permanent political consultant. And his "candidate" isn't paying close attention to his advice.

Clinton is trying to change the debate in the presidential campaign from one about the past to one about the future. Fighting about who did what in the 1980s, Clinton thinks, is a sure loser. Better to focus on who has the better plan going forward. (Remember the chorus of his campaign song? "Don't stop thinking about tomorrow.") So he has taken his approach to the airwaves.

It is easy to forget that Clinton has differed with the White House in the past about how to frame a political race. In 2010, working through Vice President Joe Biden, he urged Obama to make the case that the president had done a number of things to improve the lives of Americans in his first two years and suggested the president campaign on his record. But the White House resisted this approach, fearing the stimulus and health care reform were not popular enough to brag about and instead tried to make the Republican agenda the issue. Clinton disagreed but (mostly) kept his mouth shut about it. He doesn't seem willing to bite his tongue now.

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Clinton isn't the first president to meddle in presidential politics after his own presidency ended. So great was his dislike of Dwight Eisenhower that Harry Truman couldn't stay out of the 1952 race and even campaigned against Ike that fall. Richard Nixon made life unpleasant for Gerald Ford in the 1976 Republican primary (and seemed determined to undercut George Bush in 1992, to Clinton's benefit). But Clinton's grudge isn't personal; it's about how best to mount and run a campaign.

How much of his personal popularity Clinton will spend to win this argument is unclear, but nearing age 66, as the new poll shows, the former president has time to earn it back.

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