Long Island billionaire Robert Mercer and his family are credited with orchestrating the campaign shakeup that propelled President Donald Trump to victory, but they’ve also — with less fanfare and success — spent nearly $4 million trying to influence local and state races.

Mercer, co-CEO of the East Setauket hedge fund Renaissance Technologies, in recent years has been a top contributor — sometimes along with his wife and three daughters — to candidates for governor, attorney general and Suffolk County executive and district attorney, according to state Board of Elections records.

In all, the family since 2009 has given $3.7 million to nonfederal political committees within New York. All of the money — with the exception of $45,805 to Democratic Suffolk County Executive Steve Bellone’s 2015 re-election bid — went to Republicans or Conservatives.

Unlike the $37 million that Robert Mercer alone has given to super PACs involved in contests for Congress and the presidency, those local contributions have flown under the radar.

“We typically pay less attention to state and local elections,” said Meena Bose, director of the Hofstra University’s Peter S. Kalikow Center for the Study of the American Presidency, who has taken interest in the Mercers because of their ties to Trump advisers Stephen Bannon and Kellyanne Conway. “But in some ways, there are actually greater opportunity to exercise influence there without the same public scrutiny.”

The relative low attention to the Mercers’ local and state contributions has been the case even as they’ve often been by far the largest received by a candidate.

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In 2012, for example, Robert Mercer and his wife, Diana, Head of the Harbor residents, each gave $44,464 to Republican Suffolk district attorney hopeful Ray Perini as the Hauppauge lawyer kicked off a campaign for the next year.

Those contributions were each nine times larger than the next highest received by Perini, and totaled 42 percent of everything he raised over two years, leading up to his primary loss to the incumbent Thomas Spota, a Democrat who had GOP backing.

“On the federal level, people are almost immune to this kind of money,” said Michael Dawidziak, a Bohemia political consultant who works mostly with Republicans. “But in local elections, you’re going after a much smaller population, so the dollars go much farther.”

Still, in six of the eight local or state races that the Mercers have gotten involved in, the candidate they supported has lost.

What drives their interest in seats such as county executive and district attorney is unclear. Attempts to reach the famously private family, both through Robert Mercer’s company and Cambridge Analytica, the Manhattan voter-data firm he owns a stake in, were unsuccessful.

A spokesman for Reclaim New York, a nonprofit where Bannon once served as vice chairman — and now chaired by Rebekah Mercer — that targets local government taxes, spending and transparency, also said he was unable to make Mercer available for comment.

But state Conservative Party chairman Michael Long, whose committees have received $1.4 million from the Mercer family since 2010, said he believed Robert Mercer cares more about staying true to beliefs than racking up election victories.

“I’m thankful he and his family are there,” Long said in an interview. “He’s a person, in all honesty, that feels very strongly about a set of principles, and I think we need more people like that in our country.”

National profile rises

The Mercer family have been prominent backers of conservative federal candidates, often political outsiders, since the U.S. Supreme Court’s 2010 “Citizens United” decision, which removed the limits on political spending by so-called “super PACs.”

In 2012, Robert Mercer gave nearly $1 million to a super PAC supporting St. James businessman Randy Altschuler’s bid to defeat then-Democratic Rep. Tim Bishop in Suffolk’s 1st Congressional District. The district includes Head of the Harbor, an affluent North Shore village not far from Stony Brook University.

Two years later, Mercer supported Republican Lee Zeldin’s successful campaign to unseat Bishop. During that run, Zeldin used Conway’s polling firm.

In the 2016 presidential race, the Mercers were initially behind Sen. Ted Cruz of Texas, contributing more than $10 million to super PACs working on his behalf.

But it wasn’t until the family was identified as key drivers of Trump installing Bannon and Conway atop his campaign last summer — and daughter Rebekah Mercer took over a pro-Trump super PAC — that their political clout became a subject of fascination beyond a small circle of insiders.

First, reports last August credited Robert and Rebekah Mercer with persuading Trump to shake up his then-flagging presidential bid with the Bannon and Conway hires. The Mercers are said to be major investors in Breitbart News, the anti-establishment, conservative website that Bannon ran before joining Trump’s team.

The Trump campaign also used Cambridge Analytica data to capitalize on the electorate’s growing populist sentiments. After Trump’s upset victory, the family’s national profile continued to rise with Rebekah Mercer’s placement on the transition team and Bannon and Conway’s appointments as White House advisers.

While recent reports have said Bannon’s influence on Trump is waning, the early credit he received for shaping the president’s policies brought more focus on his longtime allies in the Mercer family. Progressive protesters last month even took the unusual step of marching outside both Robert Mercer’s offices and his estate, known as “Owl’s Nest.”

Many of the people involved in those actions said they had little idea who the Mercers were as recently as last year.

“People need to know how the Mercers’ money is filtering down,” said Myrna Gordon, a retired teacher from Port Jefferson who helped bring attention to the March 24 protest in front of Robert Mercer’s Renaissance Technologies. “This is a Long Island issue and this is a Long Island resident.”

Local giving starts in ’09

Robert Mercer, 70, a registered Independence Party member, is often described as a brilliant but reclusive man who used his skills as a mathematician and computer programmer to help build Renaissance into a wildly successful hedge fund.

He first became heavily involved in local or state politics in 2009, records show.

Beginning that summer, the Mercers — Robert, Diana, Rebekah and the other two daughters, Jennifer and Heather Sue — contributed $261,250 to former Republican Rep. Rick Lazio’s failed 2010 bid for governor, making them his top donors.

They gave another $1.3 million to the state Conservative Party, which backed Lazio through controversial television ads assailing a plan to build a lower Manhattan Islamic center.

The Islamic center, which critics labeled a mosque, never moved forward as proposed. But Lazio, of Brightwaters, lost the GOP primary for governor to Buffalo businessman Carl Paladino by 24 percentage points.

“He was certainly helpful in our fight against locating the mosque,” Long said of Robert Mercer. “I wouldn’t consider him a party mover and shaker. He’s a person who supports ideas, concepts and beliefs.”

In 2011, Robert and Diana Mercer were by far the largest contributors to then-Suffolk County Treasurer Angie Carpenter’s run for county executive against Bellone, then the Babylon Town supervisor. The Mercers gave a combined $88,000 to Carpenter, with the next highest donor topping out at $15,000.

Carpenter, a Republican who now serves as Islip Town supervisor, lost to Bellone by 14 points. She didn’t respond to numerous requests for comment.

In 2012, Robert Mercer gave $50,000 to the Suffolk Conservative Party as well as the $88,928 to Perini, a Republican who was just launching his 2013 campaign for Suffolk district attorney on a platform supporting term limits and against cross-endorsements.

Perini raised $215,274 in total.

“I have hundreds of donors. I don’t think it’s appropriate to comment on any one of them,” said Perini, who is considering running for district attorney again this year.

In 2014, Mercer was the primary funder of a super PAC supporting Republican Westchester County Executive Rob Astorino’s run for governor. He contributed $1.6 million to Rescue New York, which ran ads boosting Astorino and attacking Democratic Gov. Andrew M. Cuomo.

Cuomo won re-election by 14 percentage points. A spokeswoman for Astorino declined comment.

Bellone is anomaly

The two local or state races in which the Mercers backed the winning candidate were Astorino’s 2013 Westchester County re-election bid and Bellone’s in 2015.

Bellone also stands out as the only Democrat to receive contributions from Mercer and his family: a combined $45,805 between 2014 and 2015.

“I’ve found that most people, when you’re willing to sit down and talk, you find there are areas of common ground,” Bellone said in an interview.

He said he first reached out to Mercer in 2012, during his first year in office. When they met, Bellone said he described his efforts to downsize county government, including shrinking the size of the county workforce, trying to sell or close the John J. Foley nursing home and merge the elected offices of treasurer and comptroller.

“I think he’s someone who cares a lot about the county he lives in,” Bellone said. “I think he appreciated the work we’ve been doing to streamline government and make it more efficient.”

But County Legis. Robert Trotta (R-Fort Salonga), a leading Bellone critic, said he believes Robert Mercer would regret his contributions, citing Bellone’s contracts with police unions that have led to increased payroll costs and recent fee increases to raise revenue.

“Clearly he doesn’t know the real Steve Bellone,” Trotta said of Mercer.

While Trotta said he hasn’t met Mercer nor solicited campaign contributions from him, he sees the family’s Reclaim New York nonprofit as a potential conservative check on a Democrat-controlled county government and the police unions, which have their own super PAC and have become a dominant force in local races.

“I see him as the great hope for Suffolk County because he’s going to level the playing field,” said Trotta, whose district includes Robert Mercer’s home.

Suffolk GOP chairman John Jay LaValle didn’t return requests for comment on whether he would seek the Mercer family’s backing for upcoming county races. LaValle, who was a Trump campaign surrogate, attended a post-election party last December at Mercer’s “Owl’s Nest.”

Bellone, asked whether he thought Robert Mercer would begin contributing in large sums to LaValle’s party, or back someone to run against him in 2019, said: “He doesn’t strike me as someone who responds to pressure.”

With David M. Schwartz