WASHINGTON -- In the age of super PACs and K Street fundraisers, the hunt for grassroots donors, those giving small sums, has become less and less important on Capitol Hill. Rep. John Sarbanes (D-Md.) is trying to reverse that trend by turning his own campaign into an experiment. The three-term congressman has set out to learn how a rank-and-file House member would fare under a public system of campaign finance based on small-donor fundraising. He wants to prove that such a system would be workable.

It hasn't been easy.

Sarbanes, the son of former Sen. Paul Sarbanes who hails from a safe Democratic district stretching from Annapolis up into Baltimore County, is mimicking the concept of a public financing system by raising $750,000 in private funds from high-dollar donors -- Sarbanes does not accept PAC contributions -- with the promise that he won't touch the first $500,000 until he gets 1,000 donors each giving $100 or less and that he won't get the remaining $250,000 until those small donor contributions total more than $50,000. He's seeking small contributions through his website GrassrootsDonor.com. But in five months of chasing those donors, he's only netted around 500, far short of his goal.

The ultimate plan is to learn enough from the experiment to be able to craft a public financing bill that other members of Congress will support.

"What's been interesting is that I've been living the dream -- or the nightmare, whatever you want to call it," Sarbanes told The Huffington Post. "I've tried to model the Fair Elections Now Act in my own campaign just to see how it works. So the lens I'm bringing to where you want to make some changes in public financing is based on my own experience."

The Fair Elections Now Act, which Sarbanes has co-sponsored, is the most recent public financing bill introduced in Congress. It would require members to raise $50,000 from 1,500 grassroots donors in less than 120 days to gain access to public matching funds. For rank-and-file members like Sarbanes, reaching these numbers can prove difficult.

"There's an illusion that grassroots financing and online fundraising is easy because of what Howard Dean and the president have done," Sarbanes said. "It's been tested and proven on that level, but at the congressional level it's a much different story. It's a harder slog."

Sarbanes is no bomb thrower. He doesn't shout at the president during speeches or accuse the other party of heinous acts. He's open to compromise. Those aren't qualities that help with online fundraising.

Sarbanes noted one difficulty is persuading people to take that minute out of their day to give. "People wanna give you a $5 contribution online, but they have a million other things to do. But getting them to just sit still for 45 seconds and go in there and make the donation is, like, the hardest thing in the world," he said. "Even the president faces it. That's why he raffles off dinner with George Clooney. It's like what is that incentive to stop for that 60 seconds and go make that donation. What's our version of dinner with George Clooney?"

Most congressional lawmakers who are successful at raising money from small donors don't rely on contests to grab attention. Instead, they use bombastic language based in strong partisan appeals on national issues. The top House small-donor fundraiser for the first quarter of 2012 was Rep. Allen West (R-Fla.), who brings in the cash by calling Democrats "members of the Communist Party."

In 2010, one of the top small-donor fundraisers was Rep. Joe Wilson (R-S.C.), who saw a huge influx of little contributions after yelling, "You lie," at the president during his State of the Union speech.

With a redesigned financing system, Sarbanes said hopefully, you could focus on the grassroots and "create advantages for serious candidates. You're going to have some erratic behavior in any scenario, but over time you're going to build a system that is building a dependency on the public as opposed to a dependency on special interests and big money, which is what we have now."

The current system of never-ending fundraising and the dread of super PAC intervention is what motivated him to look for new ways to sell this model to his colleagues.

"This fundraising is consuming us," said Sarbanes. "It's impossible to overstate I think what it's doing to members and their ability to just focus on the job that they were elected to do. The collective concentration of the institution is being undermined every day by the need to fund-raise."

The rise of super PACs, more than anything else, prompted Sarbanes to look for a new model. "It wasn't until I saw what happened the last election cycle [that] I saw that it was a necessity. And here's why: super PACs come after you. Big outside money comes after you in the last stages of a campaign. ... You can't go to high-dollar donors [for help]. A lot of them tend to be maxed out, or they're part of that 'usual suspect' crowd and they're being besieged on all sides."

But "if you've built a network ahead of time of grassroots donors," he continued, you have another option. "Let's say you have 5,000 people who can give you $20 in 48 hours. That's real money; that's $100,000. At least it sends a signal to super PACs that this person isn't going to be a pushover."

Those super PACs are having a real effect on the mood in Congress. "There's a sense that you're looking over your shoulder all the time," Sarbanes explained. "The super PACs have brought an element of fear into the equation. The fact that they can bring this money into the campaign, basically ambush you out of nowhere, and you'll have no way to fight back."

Sarbanes' experiment has brought praise from supporters of public financing. Harvard Law professor Lawrence Lessig, the author of "Republic, Lost: How Money Corrupts Congress -- And a Plan to Stop It," called the effort an "ingenious idea."

"This is not a one-off experiment," said Nick Nyhart, president of the campaign reform nonprofit Public Campaign. "He's doing this to craft a system where people can rely on small donations and money from a public fund."

The real question that Sarbanes must answer, though, is whether other politicians will be interested in the lessons he's learning from his grassroots donor experiment.

"There's a lot of interest in it," Sarbanes said. "I recognize that a lot of my colleagues in tough races can't do this kind of experiment now. Others who may not be in difficult races, it's too late for them to implement something like this this cycle. But they are interested and intrigued in what kind of techniques we're trying to employ."

Ryan Grim contributed reporting to this article.

CORRECTION: An earlier version of this article understated the amount of private funds that Sarbanes has deferred, and clarified the amount of small-donor contributions he intends to raise before using that money.

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