There’s an old Irish saying that goes, “The best way to keep loyalty in a man’s heart is to keep money in his purse.— And for American lawmakers and political interests focused on maintaining peace in Northern Ireland during the past decade, keeping a former militant group in check means making sure its political coffers are flush with cash.

By its own estimates, the Irish political party Sinn Fein has raked in more than $10 million from U.S.-based donors since it first legally passed the collection plate here nearly 15 years ago.

“Without the funding from the U.S., Sinn Fein would be hard-pressed to be doing what it’s doing,— said Notre Dame University professor emeritus Jay Dolan, author of “The Irish Americans: a History.— “They are now a legitimate party, but they grew out of the revolution.—

In the past six years alone, the International Brotherhood of Teamsters, the Laborers’ International Union of North America and other organized-labor groups have handed over more than $120,000 each in campaign donations to the New York-based Friends of Sinn Fein, according to CQ MoneyLine.

And although they tend to leave their checkbooks at home, Irish-American Members of Congress continue to play a vital role in helping Sinn Fein shed its affiliation with the Irish Republican Army, an inactive paramilitary group that clashed with the U.K. in a prolonged conflict that formally ended 11 years ago.

“We’ve had great help on both sides of the aisle,— Friends of Sinn Fein President Lawrence Downes said of his supporters in Congress. “The core group is terrific. … We rely on them all the time.—

Downes declined to provide specifics on Members’ activity with Sinn Fein. Still, he would confirm that Reps. Peter King (R-N.Y.), Richard Neal (D-Mass.) and Joe Crowley (D-N.Y.) remain loyal behind-the-scenes supporters of his group, showing up at fundraisers and meeting with Sinn Fein officials when they are in town.

Neal, who met with Sinn Fein President Gerry Adams during President Barack Obama’s inauguration, called the Northern Ireland peace process — in which the United States played a central role — “a very successful dimension to American foreign policy.—

“I have always thought that convincing Sinn Fein to adopt mainstream politics was the way forward,— Neal said.

Crowley, who has known Downes since he was a teenager, agreed, saying that former President Bill Clinton “recognized that Adams and others in the leadership had taken risks for peace and that we should also take a risk for peace by adding a voice to the political discussion.—

These lawmakers believe the Clinton administration was right to kick-start Sinn Fein’s path to legitimacy by allowing it to hit up America’s vast Irish communities for donations; after all, America had surreptitiously bankrolled IRA terrorists for decades.

“Ireland has been coming here for a 100 years to raise money [and] the way they raised money here for Sinn Fein and the IRA was through the pubs and the bars,— Irish historian Dolan said. “They did a lot of fundraising, but it wasn’t on the up-and-up. It was more smuggling guns and smuggling money.—

But in March 1995, Clinton formally lifted a long-standing ban against Sinn Fein fundraising after an intense lobbying campaign by Members, including Neal, King and then-Rep. Thomas Manton (D-N.Y.), Crowley’s predecessor and mentor. Since then, Sinn Fein has held fundraisers regularly in New York, Washington, D.C., and elsewhere, raising money to buy property and office equipment at home while maintaining its beachhead in the United States.

“This was all about having Irish Republicans channel their energies, their grievances, their hopes and aspirations into politics and away from violence,— Downes said. “Well, politics costs money.—

Unions, which historically have had heavy Irish-American membership, also took up the cause. Downes said the Laborers’ International Union of North America has been particularly supportive of its efforts in the United States.

Along with Adams, Laborers’ International President Terence O’Sullivan is expected to speak next month at a U.S. event hosted by the political party.

With the peace intact, Sinn Fein is not slowing its fundraising operations here, Downes said. According to Justice Department records filed under the Foreign Agents Registration Act late last year, the party recently raised more than $60,000, a total that included contributions from the Teamsters and the Communications Workers of America.

“In 1994, ’95, it would not have happened without America. … The war would have gone on for quite a bit longer had America not gotten involved,— Downes said. “As time goes on, the American government’s role has become less important.—

“But the Irish-American diaspora remains critical to the process,— he said.