Washington ( CNN ) -- How things change . In 2008 , after a bruising primary battle with Hillary Clinton , then-Sen. Barack Obama was on the outs with former President Bill Clinton . This election cycle , Clinton is one of Obama 's most visible surrogates . Obama and Clinton were to appear together Monday night at three New York City fundraisers , which are expected to bring in millions of dollars . In April , the two appeared side by side at the home of longtime Clinton supporter and former Democratic National Committee Chairman Terry McAuliffe , raising $ 2.1 million for the Obama campaign and the DNC . Clinton and Obama hit up the Big Apple . The Obama campaign is relying heavily on Clinton , tapping into his network of wealthy donors and featuring him in campaign ads . Clinton is also expected to hit the trail to rally voters leading up to the November election . `` Clinton just wants to help , '' a source close to the former president said . `` His message is ' I know what it takes on the economy , and Obama is doing the right thing . ' They 're not going to make the mistake of the Gore campaign . They 're not going to put [ Clinton ] on ice . '' Obama 's relationship with the Clintons has had its ups and downs . In 2007 , the former president took aim at the then-junior senator from Illinois as inexperienced . `` You know , I 'm old-fashioned . I think it really -- I think a president ought to have done something for other people and for his country when you pick a president , '' Clinton said . `` I mean when is the last time we elected a president based on one year of service in the Senate before he started running ? '' In early 2008 , when Obama won the first-in-the-nation Iowa caucuses and emerged as a real contender , he entered into an all-out feud with the former first couple . The tussle was on full display during a January 2008 debate . `` I 'm here , not my husband , '' Hillary Clinton said to Obama . `` I ca n't tell who I 'm running against sometimes , '' Obama retorted . The Clinton source says , `` He held a grudge , she did n't . '' Obama picking Hillary Clinton as his secretary of state helped heal some wounds . And he 's looked to Bill Clinton for help since taking office , hosting him at the White House during contentious negotiations with Congress in December 2010 . `` I have a general rule , which is that whatever he asked me about my advice , and whatever I say , should become public only if he decides to make it public , '' Clinton told reporters then . As Obama struggles to appeal to white , working-class males , he hopes Clinton can woo those voters in key Southern and Rust Belt states . You would n't call the two men best of friends , but the lines of communication between the White House and the Clinton circle are open , sources in both camps say . But even as the two are now on the same team , they 're not always reading from the same playbook . While the Obama campaign tries to make a liability of presumptive Republican nominee Mitt Romney 's past as the head of a private equity firm , Clinton recently punched a hole in what has been a central campaign argument . `` I think he had a good business career , '' Clinton said of Romney last week on CNN 's `` Piers Morgan Tonight . '' `` There 's no question that in terms of getting up and going to the office and , you know , basically performing the essential functions of the office , the man who has been governor and had a sterling business career crosses the qualification threshold . '' Romney smiles at Clinton compliment . Clinton later clarified his remarks , but the damage was done . Obama campaign reacts to Clinton on CNN .
The Obama campaign is relying heavily on Bill Clinton 's connections . `` Clinton just wants to help , '' a source close to the former president said . Obama hopes Clinton can woo white , working-class men in key Southern and Rust Belt states . But he also needs black voters who are more likely to vote for him than other groups.