She owns a cookie store. He loves model trains. They both hate the Clintons. And beyond that, not much is clear about the motivations of the Mercer father-daughter duo of Republican megadonors who have become two of the most powerful people in the country over the last 18 months.

Hedge-fund billionaire Robert Mercer and his daughter Rebekah were among the earliest and strongest backers of Donald Trump while other elite donors still disdained him. It turned out to be a good investment. But now, with their favored candidate freshly installed as president of the United States, it remains unclear what they believe, or what they hope their investment will yield.

The Mercers have been a quiet but constant presence in the background of Republican politics since the beginning of the 2016 cycle. They started the campaign as backers of Ted Cruz, pouring millions into one of the main super PACs supporting his candidacy. Their data firm, Cambridge Analytica, was hired by the Cruz campaign. They switched to support Trump shortly after he clinched the nomination, and he eventually hired Cambridge Analytica, as well. Their top political guru is Steve Bannon, the former Breitbart News chairman and White House chief strategist. They’re close, too, with Trump’s campaign manager Kellyanne Conway, who also has a senior role in the White House. They never speak to the press and hardly ever even release a public statement. Like Trump himself, they’ve flouted the standard playbook for how things are done in politics.

Clues to their policy preferences can be found in their family foundation’s pattern of giving. For example, they have given more than once to groups questioning climate-change science. But their donations have flown to groups all over the conservative political map, ranging from libertarian organizations to movement conservative groups to the Koch brothers’ Freedom Partners Action Fund to Breitbart. That scattershot approach suggests the family has some ideological flexibility.

No one seems to know what motivates the Mercers or what policies they want to see enacted, even people who have worked closely with them or for projects funded by them. While they’ve poured money into conservative causes, they’ve also invested in projects explicitly aimed at overturning the modern conservative movement, like Breitbart News, in which they reportedly invested $10 million, and Trump himself. And the mystery of their ideological motivations is made all the more striking by their success in helping Trump reach the White House. A recent Wall Street Journal story on the Mercers concluded: "It isn’t clear what specific policies or positions, if any, the Mercers are seeking for their support of Mr. Trump."

“All I can take away is that they just want to be power players,” said a former Breitbart News staffer, who spoke on condition of anonymity because of a non-disclosure agreement. “I don’t know what their principles are. I don’t know how you switch from Ted Cruz to Donald Trump so quickly.”

“Most of these people I think I understand,” said a Republican operative who has been engaged on several Mercer-led efforts. (Like most people quoted in this story, the operative declined to be identified for fear of legal or professional consequences for speaking publicly about the Mercers.) “I don’t understand the Mercers.”

Rebekah Mercer “talks business. She talks data, she talks trends, she talks messaging,” said another Republican operative who has worked with the Mercers. “I have never really been in her presence where she’s talked policy.”

Asked to describe what’s motivating them, Bannon himself was vague.

“Really incredible folks,” Bannon said in an email. “Never ask for anything. Very middle class values as they came to their great wealth late in life.”

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Robert Mercer got his start at IBM, working there for over 20 years. He went to Renaissance Technologies in 1993. It’s there that Mercer, already well into middle age, became wealthy. Renaissance, based in East Setauket, Long Island, includes three hedge funds managing over $25 billion in assets, as well as the mysterious Medallion Fund, an employees-only fund that has made its investors unimaginably rich. Mercer’s co-CEO is Jim Simons, a major donor to Democrats; one Republican operative with connections to the Mercers who spoke on condition of anonymity joked that the pair were trying to “hedge the political system.”

Rebekah, known as Bekah, is one of Bob and Diana Mercer’s three daughters. Along with her sisters Heather Sue and Jennifer (“Jenji”), she owns Ruby et Violette, a cookie store in New York (the cookies are now sold exclusively online). Rebekah, 43, is married to a French Morgan Stanley executive, Sylvain Mirochnikoff, with whom she has four children. Mercer did not respond to requests for comment for this story.

Bob Mercer, 70, is an enigmatic figure who has a reputation for rarely speaking publicly. Nearly everyone spoken to for this story used some variation of the word “brilliant” to describe him. There’s a touch of eccentricity, too; “I know a couple things you can bond with Bob Mercer over is he hates the Federal Reserve and loves model trains,” said one Republican operative who has worked on Mercer-backed initiatives. (Mercer once sued a model train manufacturer, alleging that he was overcharged for a model train set installed in Owl’s Nest, his expansive Long Island estate).

Whatever her actual beliefs, there’s one thing upon which people who have worked with Rebekah Mercer agree: She has a keen understanding of politics and likes to be involved in the day-to-day running of projects she’s involved in. Many donors like to play strategist, much to the annoyance of the actual strategists in their employ. But Mercer appears to be more successful at it than most.

“Almost all donors want to pretend they’re Karl Rove. They all want to play political mastermind,” said one of the Republican operatives who has worked on Mercer-funded projects. But “I would say that Rebekah is as smart at politics as you could be without ever having been at the grunt level.”

“Her political instincts were always on the money,” said Hogan Gidley, a former Mike Huckabee aide who served as spokesman for the Make America Number One PAC which became the Mercers’ pro-Trump vehicle during the general election. “We would be talking about how a certain ad should look or changes we should make to an ad, and she would just offer an idea that would just elicit instantaneous agreement. It wasn’t because they were largely funding the PAC, it was because she was right.”

Gidley said Mercer was on every conference call related to the super PAC’s operations. Even so, he didn’t get a clear sense of Mercer or her father’s ideology.

“They’re libertarians who understand that they might have to make compromises with social conservatives,” said one person in the non-profit world who is a recipient of multiple Mercer grants. “They’re just as at home at the Cato Institute as they would be at the Heritage Foundation on general issues.”

The Mercers, the non-profit activist said, appeared to have two goals this election cycle: “They’ve been fighting the Clintons forever, and they wanted to back the winning horse.”

That first goal has been clear for some time. The Mercers have for years had their hands in the cottage industry of anti-Clinton activity in and around the conservative movement. According to tax records from the Mercer Family Foundation, they gave nearly $3.6 million to Citizens United between 2012 and 2014, which sued for access to Clinton Foundation-related emails last year and whose president David Bossie also got a senior job on the Trump campaign. They’ve also invested in the Government Accountability Institute, which publishes the conservative author Peter Schweizer. Schweizer’s book Clinton Cash was an influential source of talking points for Trump allies during this election cycle, providing fodder for one of Trump’s early salvos against Clinton in a speech in June and regularly populating the pages of Breitbart. Bannon co-founded GAI with Schweizer; Rebekah Mercer has sat on the board.

The Mercers’ activities during the election cycle are among the clearest public evidence of how their beliefs, whatever they might be, translate into action.

At first, the Mercers went in for Cruz. They backed Keep the Promise 1, one of the main super PACs supporting Cruz, to the tune of $11 million. Like other campaigns with which the Mercers have been involved, including Trump’s, the Cruz campaign engaged the Mercers’s data firm Cambridge Analytica. Cruz campaign officials clashed with Cambridge over the particulars of the contract and lodged complaints about the product itself, according to multiple sources familiar with what happened; in one instance, the Cruz campaign was paying for a database system, RIPON, that had not been built yet, leading to a contentious argument. They also caught wind of work Cambridge had done for the Ben Carson campaign; working on more than one primary campaign is a no-no for vendors. Elsewhere in Mercer-world, there were other signs of trouble when it came to Cruz. In January, before the primaries had even begun, Breitbart News began attacking Cruz, insinuating that he was ineligible to be president because of his Canadian birth (a line also in heavy use by Trump at the time). Meanwhile, the Mercers were still publicly behind Cruz.

“Cambridge Analytica's data science team had an excellent relationship with the Cruz campaign: we were part of the campaign starting from day one and all the way through the primaries and caucuses until the final day, and we continue to work with many of the principals from the campaign,” a spokesman for Cambridge Analytica said. On the work they had done for the Carson campaign, the spokesman said “Cambridge Analytica is large enough to work on more than one campaign at any given time, and we take FEC firewall regulations very seriously. We would not work with multiple clients if we did not have the scale to provide devoted resources to ensure full compliance with firewalling procedures.” And on RIPON, the Cambridge Analytica spokesman said “Ripon was being used by many senatorial and gubernatorial candidates in the 2014 mid-terms. Some bespoke modifications were requested by the Cruz campaign and we were of course happy to make those for them.”

The Breitbart stories were troubling to Cruz staff, who had seen Breitbart as an ally and who didn’t think they had any reason to doubt the Mercers’ loyalty.

What Cruz’s staff may not have taken into account was the behind-the-scenes influence of Steve Bannon.

“I don’t think [the Mercers are] as nationalistic as Steve,” said a Republican operative who has worked for the Mercers. “Steve is an unapologetic nationalist. I don’t think the Mercers are as much.” But “they share a real disdain for elitism. That’s what sort of binds them together.”

Another of the Republican operatives described Bannon as the “Obi-Wan Kenobi” to Rebekah Mercer, and a third was even more pointed: “Svengali.” Bannon is “really, really, really influential” with Mercer, said the former Breitbart employee. The Mercers, the former employee said, made their wishes known through Bannon, who would sometimes cite the company’s financial backers as a reason for Breitbart not to do a story. Bannon didn’t respond to a request for comment about this.

That highlights a third apparent goal, which became clearer over the course of the campaign: dismantling the establishment.

The Mercers made two public statements over the course of the campaign.. The first came after Ted Cruz’s dramatic speech to the Republican convention in which, amid booing, he refused to endorse Trump and told people to “vote your conscience.”

“Last summer and again this year, Senator Ted Cruz pledged to support the candidacy of the nominee of the Republican Party, whomever that nominee might be,” the Mercers said in a statement to The New York Times afterward. “We are profoundly disappointed that on Wednesday night he chose to disregard this pledge. The Democratic Party will soon choose as their nominee a candidate who would repeal both the First and Second Amendments of the Bill of Rights, a nominee who would remake the Supreme Court in her own image. We need ‘all hands on deck’ to ensure that Mr. Trump prevails. Unfortunately, Senator Cruz has chosen to remain in his bunk below, a decision both regrettable and revealing.”

The second came after the release in October of the Access Hollywood tape that featured Trump boasting to Billy Bush about groping and kissing women without permission. The tape was too much for many of the Republicans who had begrudgingly come around to Trump; some rescinded their endorsements, and there was pressure on Trump to drop out of the race.

But not from the Mercers, who dismissed the tape as “locker room braggadocio” in a statement to the Washington Post:

“America is finally fed up and disgusted with its political elite. Trump is channeling this disgust, and those among the political elite who quake before the boombox of media blather do not appreciate the apocalyptic choice that America faces on Nov. 8.”

The rare statement provided an unusual glimpse into the Mercers’s views, reflecting a disdain for an elite political class of which they themselves are members.

This disdain could be one reason why the Mercers have not constructed their own donor network to rival  that of the Koch brothers, or Paul Singer. Most elite Republican donors tend to favor establishment candidates like Jeb Bush and Marco Rubio. The Mercers, tied as they are to the anti-establishment fervor sweeping the Republican Party in recent years, don’t fit in. But their distance from their peers has only made them more relevant.

While everyone respects Rebekah Mercer as serious and smart, several sources said she could be prickly, and one of the operatives who has worked with her described her as a “difficult person.” That reputation may make it harder for her to build the relationships necessary for consolidating a network of other donors.

Mercer exerted a considerable amount of behind-the-scenes influence during the transition, weighing in even on subplots like choosing a new chair of the Republican National Committee. She had an official spot on the transition executive committee. But her role going forward is less clear. She’s expected to help lead an outside group pushing the president’s agenda in the vein of Obama For America. It’s not clear what other donors will be involved. Though already there are signs of trouble; Politico reported that the Mercers were backing out of the group, which is to be led by Trump campaign digital director Brad Parscale and Mike Pence aide Nick Ayers. It’s unclear how the situation will resolve itself.

“Whether she tries to get other donors involved with her own thing remains to be seen,” said one of the Republican operatives who has worked with the Mercers. “She always tries, she’s just not very good at it. She’s not a people person … But she seems serious and this is more than just a hobby for her.”