While Clinton predicted an Obama victory in November and said the president's proposals are better for the economy than Romney's, he also said that "the man who has been governor and had a sterling business career crosses the qualification threshold."
The mixed messages came just ahead of Monday's trio of Manhattan fundraisers where Obama and Clinton are set to showcase a newfound alliance that has evolved after years of mistrust and tension.
"Bill Clinton is not someone who is easily controlled and sometimes he says what he thinks," said Julian Zelizer, a professor of history and public affairs at Princeton University in New Jersey. "It's something the Obama campaign will have to deal with and accept in exchange for his support."
The iciness between the two has thawed since the protracted 2008 Democratic primary between Obama and his then-rival turned secretary of state, Hillary Clinton, the former first lady.
Still, people knowledgeable about the relationship say that while the two are in a good place, it isn't one they describe as warm. Obama, 50, and Clinton, 65, are respectful and friendly, without being effusive.
During an hour-long private dinner last month before a fundraiser at the home of Terry McAuliffe, a former Democratic National Committee chairman, Obama and Clinton talked politics, energy issues and foreign policy. They discussed their mutual love of basketball. After a $20,000-a-plate dinner with 80 donors, they jointly spoke to a crowd of 500, each of whom paid at least $1,000 to see them side-by-side.
"Well, you guys get two presidents for one out of this event, which is a pretty good deal," Obama said at McAuliffe's McLean, Va., home.
The president's campaign has solicited Clinton's help at all levels of the re-election effort, including messaging, targeting specific demographic groups, and fundraising for the campaign and Priorities USA Action, an independent political committee founded by former Obama aides.
He praised Obama's handling of the economy in a 17-minute campaign video by Davis Guggenheim, an Academy Award winning director, and aides say they are considering using more footage from the interview in the next five months. Obama's strategists also plan to dispatch Clinton to Midwestern battleground states where he can highlight an asset he has and Obama lacks: a strong record of economic growth.
"I don't think there's a state I wouldn't put him in," said Jim Messina, Obama's campaign manager. "There isn't anyone he couldn't talk to. He's just - he's Bill Clinton."
At the request of Messina and Patrick Gaspard, DNC executive director, Clinton engaged in Tuesday's Wisconsin recall election of Republican Governor Scott Walker, a priority for organized labor.
"The great thing about not being president is you can say whatever you want," Clinton told a Milwaukee crowd on June 1, standing alongside Walker's Democratic challenger, Tom Barrett, and holding up a piece of paper bearing his handwritten speech notes. "Nobody has to care anymore, but you can say it."
Later that day, Clinton traveled to Paterson, N.J., where he campaigned for Rep. Bill Pascrell Jr., who is running against Rep. Steve Rothman - who has the backing of Obama. His appearance served as another reminder that the former president will cut his own path.
Clinton's political role was mapped out last November when Messina, Gaspard and David Axelrod, Obama's chief political strategist, made a trip to Clinton's Harlem office where they outlined a plan, solicited his input, and personally asked for his help.
They discussed how Clinton could be most useful to the re- election effort, how to best attack Romney and Messina gave an hour-long briefing on the states in play. The former president still displayed an encyclopedic knowledge of polling data, regions and media markets, according to one of the participants.
The alliance could benefit both men.
Obama will be aligned with a president who served during a time of economic growth and has a gift for communicating with voters, particularly women, independents, and working-class voters.
Clinton regains a central political role and his efforts could benefit his wife if she decides to seek office in the future.
It should also put behind charges by Obama and Clinton allies in 2008 that the former president injected race into the Democratic primary battle by comparing the president's South Carolina win to Jesse Jackson's victories there in 1984 and 1988. Clinton, who was dubbed America's first black president by author Toni Morrison, still resents that accusation.
That lingering angst is one reason it's taken years to build a bridge between 44th and 42nd presidents.
Republicans, knowing the value of Clinton and his broad appeal, are looking for any opportunity to puncture holes in the alliance. Romney last month said Obama should take an example from Clinton and strive toward greater bipartisanship.
"Maybe it was a personal beef with Clintons," he said, alluding to the complicated relationship that's played out in the public stage.
After hearing Romney's comments that day, Clinton told associates that when it comes to Obama, he's "all in."