President Obama greets supporters during a fundraiser at the Aragon Ballroom on Aug. 3 in Chicago. (Scott Olson/Getty Images)

Even with low approval ratings and an uncertain path to reelection, President Obama is exceeding expectations in one area: His campaign is doing far better at attracting grass-roots financial support this year than his Republican rivals or his own historic effort in 2008, according to new contribution data.

The sheer scale of small donations, totaling $56 million for Obama and his party, has surprised many Democratic strategists and fundraisers, who feared that a sour economy would make it difficult for Obama to raise money from disenchanted and cash-strapped voters.

A Washington Post analysis shows that nearly half of his campaign contributions, and a quarter of the money he has raised for the Democratic Party, has come from donors giving less than $200. That’s much higher than it was in 2008 and far beyond what the best-funded Republicans have managed.

Mitt Romney and Rick Perry, the leading GOP fundraisers, have embraced a traditional approach, focusing on big-dollar contributors who can fill coffers without the high overhead costs of a campaign targeting small donations, the analysis shows.

Business executive Herman Cain has had more success with small donors, who have helped propel a surge in contributions to the candidate in recent weeks.

A grass-roots-oriented campaign presents opportunities and risks for Obama, who is weighed down by the stagnant economy, a glum public mood and signs of disaffection among Democrats.

The focus is rooted in the belief that donors, even if they give only a few dollars, are more committed to their candidate than those who have not written a check.

“The number of small donations shows who it is that supports this president and who put him there,” said Katherine Hahn, a self-described “mom and artist” from Evergreen, Colo., who gives Obama $25 a month. “It wasn’t the powers that be so much as it was people like me.”

But relying on donors of modest means could limit the fundraising ability of the president, whose campaign is already showing signs that it is struggling to bring in big donations. Fewer than 6,000 contributors had given Obama $2,500 or more through September.

That compares with more than 8,000 maxed-out donors giving to Romney. And if Romney wins the nomination, the same people will be able to give much larger amounts to his campaign and the Republican Party.

‘Broad-based’ strategy

“We always knew we needed to build a broad-based support network, and we try not to rely too much on one thing,” Obama campaign manager Jim Messina said in an interview. “Our experience is that people who give become volunteers, and people who volunteer become donors. We want to build a relationship with them.”

Republicans say their eventual nominee will have plenty of time to build widespread excitement after the primaries.

“The role of small donors is the same as large donors — to participate in our campaign community, one that is eager to replace President Obama with a new leader who can get our country back on track,” said Romney spokeswoman Andrea Saul. She said 83 percent of Romney’s donors in the third quarter gave less than $250.

A central part of the Obama campaign’s grass-roots strategy is in swing districts such as Jefferson County, Colo., west of Denver. The county, home to Coors Brewing Co. and the Colorado School of Mines, leans Republican but went decisively for Obama in 2008.

In interviews with a cross section of donors from the area, Hahn and others said they are backing Obama’s reelection, even if they are disappointed in some aspects of his presidency.

“I think he’s trying very hard,” said retiree James Dunn of Wheat Ridge, who has given Obama $225 so far this cycle. “I am 86 years old, and I have never seen such a concentration of lies against a decent man.”

Pat Angel, 71, of Morrison said she gives $25 to the president’s campaign when she can, with ann additional $10 per month from her husband for the Democratic National Committee. Angel helps run the family business, Angels Bail Bonds, and works full time at Wal-Mart because she cannot afford to retire.

Despite her struggles, Angel remains loyal to Obama.

“I honestly think he is the only hope,” she said. “When I look at the Republican slate, I shudder.”

But there are many donors who supported Obama in 2008 who have not returned. Michael Glode, 64, a registered Republican and medical professor in Golden, gave Obama $210 in 2008 — the first political donation of his life — but will not do so again.

“His biggest mistake was not going directly to the American people with his oratory skills,” Glode said. “I’m pretty disappointed in American politics.”

This year, about 45 percent of the $90 million raised by Obama’s reelection campaign from April through September came from donors who each gave less than $200 in aggregate donations, according to The Post’s analysis of Federal Election Commission records. When money that Obama has helped raise for the DNC is included, the figure is 36 percent.

Either way, the share is higher than in 2008, when about a quarter of the $755 million raised directly for Obama’s campaign came from the smallest donors.

About 9 percent of the $32 million raised by Romney through September came from small donors; the figure for Perry, who raised $17 million, was 4 percent. Several other GOP candidates have notably high percentages of small donors, but their overall fundraising is modest.

New Obama donors

One surprise for the Obama campaign was the discovery that, out of more than 1 million donors this year, half had never given to him before.

Supporters who make revolving donations get special ­T-shirts, monthly conference calls with Messina and other goodies as part of “Team 2012,” an effort with more than a passing resemblance to a public-radio fundraising drive. Donors who give as little as $3 can enroll to win dinner with the president.

The campaign has also mounted a program to contact every 2008 supporter by phone or in person, and an effort to recruit students and other young adults.

“The fundamental thing that we believe, and that we bring to all the work online and offline, is that people take action on behalf of a campaign because they feel an emotional connection with it,” said Teddy Goff, the campaign’s digital director. “We are much more focused on how we can give people access to the campaign than on thinking up new tricks or gimmicks.”