All the attention directed at the mega-donations that business titans are making in the race for the White House this year has eclipsed an equally critical aspect of the fund-raising war - courting the little guys. And in that boisterous battle of e-mails, celebrity-sponsored contests, and online credit card charges, President Obama is clearly winning.

As of the end of April, 43 percent of the donors who contributed to the Obama campaign gave $200 or less, generating a total of $88.5 million, according to the Campaign Finance Institute, a nonpartisan Washington research group. By contrast, only 10 percent of those who gave to former governor Mitt Romney’s campaign had made donations of $200 or less, accounting for $9.8 million.


The gap in small-donor fund-raising shows that Obama and Romney are following radically different paths to raising the hundreds of millions of dollars that each will need to run a competitive race.

While Obama has embarked on a grass-roots fund-raising drive based largely on small donations, as he did four years ago, Romney has relied on contributions from more generous donors to his campaign, and unlimited contributions from wealthy individuals and corporations to the independent super PACs sympathetic to his candidacy.

Although both models may prove equally successful when it comes to the bottom line, Romney’s struggle to match Obama in contributions from small donors who give $200 or less may be a sign that he is still having trouble corralling support from the Republican Party’s conservative base.

“Small donations matter a lot because they indicate enthusiasm and energy for a campaign,’’ said Rob Gray, a Boston political consultant who was an adviser to Republican John McCain’s 2008 campaign. “The shortage of small donors means the Republican and conservative base is not jumping on board with Romney in big numbers - at least not yet.’’


Small donors are also important because they are a renewable resource. Once a small donor has supplied a candidate with an e-mail address - a donation that, initially, can be more valuable than cash - the donor can be solicited repeatedly with little concern that the donor will bump up against the limit on campaign contributions by individuals.

In addition, small donors are often the volunteer foot soldiers of a campaign’s ground operation, making phone calls on behalf of the candidate, posting lawn signs, and driving voters to the polls on Election Day.

“Obama has a huge advantage there,’’ said Philip W. Johnston, an Obama fund-raiser and former chairman of the Massachusetts Democratic Party, noting Romney’s reliance on wealthier donors. “Wall Street bankers are unlikely to be knocking on doors in the neighborhood anytime soon.’’

In recent weeks, the importance of small donors has taken center stage in both the Obama and Romney campaigns.

Last month Obama staged a high-profile fund-raiser at the Los Angeles home of Hollywood star George Clooney and raised a reported $15 million - much of it from small donors who were asked to make a $3 contribution on the Internet in return for a chance to attend.

The Obama campaign is planning another similar event - blending a high-roller fund-raiser with a small donor contest - later this month when “Sex and the City’’ star Sarah Jessica Parker is slated to host the president and Michelle Obama at her New York City home.


The Romney campaign, meanwhile, is raffling off a private dinner with the candidate and real estate businessman Donald Trump - without any contribution required. And last Thursday night, the campaign was scheduled to accept the final entries in a similar raffle for a chance to “Grab a Bite with Mitt’’ and Ann Romney.

To be sure, Obama is holding his share of fund-raising events for wealthy donors. And Romney is using the Internet to generate small campaign contributions.

But records filed with the Federal Election Commission and research by nonpartisan analysts show a wide chasm between the two campaigns when it comes to small contributors.

To make up for a dearth of small donors, Romney has had to rely on those who gave $2,500 to his primary campaign - the legal maximum. Through the end of April, when the candidates filed their most recent fund-raising supports, 62 percent of donors to the Romney campaign had given $2,500, while only 16 percent of Obama’s donors had contributed that amount.

Individual donors who gave $2,500 to either of the candidates’ primary campaigns may contribute another $2,500 toward the candidate’s general election campaign.

“That’s a very high percentage of funding from donors who have given the maximum,’’ said Anthony Corrado, the CFI board chairman and a Colby College professor, speaking of the Romney donors. “What it suggests is, Romney has not been very successful, at least through the primaries, of tapping the support of small, grass-roots donors. In fact, he’s been remarkably unsuccessful.’’


Ryan Williams, a spokesman for the Romney campaign, noted that during a one-month period between mid-March and mid-April, donors who contributed $200 or less to the Romney campaign jumped by about 27 percent, from 47,500 individuals to 60,500, adding that the campaign is heartened by the uptick.

“We’re getting a tremendous response from small-dollar donors who are coalescing around Governor Romney’s pro-jobs message,’’ Williams said.

In addition, the Republican National Committee has attracted more money in small donations than the Democratic National Committee.

But Romney still lags far behind Obama in overall contributions from small contributors. “What we’re seeing are two very different models of fund-raising,’’ said Bob Biersack, a former Federal Election Commission staffer who is now a senior fellow at the Center for Responsive Politics, another nonpartisan research group.

Obama’s continuing reliance on small donors is notable because, historically, the powers of incumbency have attracted large campaign contributors eager to secure access to the White House as part of their effort to protect or advance business interests.

“What you would generally expect for an incumbent’s reelection campaign would be a much more traditional fund-raising model,’’ Biersack said. “That’s happened to some extent, but it’s still the case that Obama is raising nearly half his money from small donors - and it’s a lot of money.’’

As of April 30, the Obama campaign had raised $217 million compared with the $98 million that had been raised by the Romney campaign. Those amounts do not include money raised by the national political parties or the unlimited donations to independent super PACs.


Corrado said he expected Romney to receive a larger surge in small donor contributions in April for a number of reasons.

First, after emerging as the presumptive “anti-Obama’’ candidate, Romney might have received more contributions from small donors who backed one of his more conservative primary opponents, such as former senator Rick Santorum or former House speaker Newt Gingrich. Instead, Corrado said, those small donors are probably either sitting on the sidelines or making small contributions to more conservative candidates for the House and Senate.

Corrado also said he expected to see more small donors giving money to Romney in April because of technological advances in social networking that make it easier than ever to give to a candidate, and, finally, because polls are showing a close race between Obama and Romney.

“Generally speaking, competitive races tend to drive smaller donors,’’ he said.

Michael Rezendes can be reached at rezendes@globe.com. Follow him on Twitter @RezGlobe.