Robert Mercer is a little-known hedge-fund billionaire who, along with his daughter Rebekah, played a key role first in making Trump a candidate, and then in shaping his White House staff. Jane Mayer is the first to file an in-depth report on the elusive figure. She’s a staff writer for The New Yorker and author of several award-winning and bestselling books. Her latest, Dark Money: The Hidden History of the Billionaires Behind the Rise of the Radical Right, was named one of the ten best books of the year by The New York Times—it’s out now in paperback. This interview has been edited and condensed; listen to the full interview on the Start Making Sense podcast.

Jon Wiener: To do this story you spoke with the prince of darkness himself, Stephen Bannon. What was that like, and what did he tell you about Robert Mercer and his daughter Rebekah?

Jane Mayer: I was on the edge of my seat to see what Bannon was like, pacing around and waiting for him to call. Finally he did. He turns out to be quite engaging and a lot of fun to talk to. He said the Mercers had launched the Trump revolution, and that, more than any other donor in the last four years, they had the biggest impact of anyone in putting Trump in power. He was pretty up front about the whole thing.

JW: You say Bannon was a lot of fun to talk to. Is Robert Mercer a lot of fun to talk to?

JM: Robert Mercer wouldn’t speak with me, and that’s not unusual. He doesn’t speak almost to anyone. I quote someone who said that he prefers the company of cats to humans.

JW: You say he heads an incredibly lucrative hedge fund. Who exactly is Robert Mercer, and how rich is he?

JM: He is the co-CEO with one other man of something called Renaissance Technologies. It’s hard to know exactly how rich he is, but he is listed by Institutional Investor as making approximately $135 million a year, and that would have been true for at least the last 10 years or so. He’s getting up there in the billionaire category, I would think.

That enabled him, and his family, to indulge any kind of whim they had. One of the things that he wanted to buy, and that his middle daughter Rebekah wanted to buy, was an America that more closely fitted their political point of view. So they poured money into that project.

JW: Let’s talk about that political project. You say Robert Mercer basically never speaks, nevertheless you were able to find out quite a lot about his political ideas. What does Robert Mercer say about racism in the United States?

JM: He believes that white racism doesn’t exist in America. He says there’s only black racism. He says that the civil-rights movement has made blacks less well off. He thinks that the Civil Rights Act was one of the great mistakes in modern American history.

JW: What does he say about the dangers of nuclear war?

JM: He got into an argument with somebody he worked with in which he argued that Hiroshima and Nagasaki, and nuclear war in general, were not as bad as people think. It’s survivable, he argues, and not only that; the radiation from it, he suggests, from the fallout, is good for people. He’d say, “Well, you know, in the blast zone it wasn’t so great for the Japanese,” but outside of the blast zone, he would claim, it was great for the Japanese health.

JW: And you have a fascinating story about what he says about the value of cats.

JM: He has, according to his colleagues, a theory of humans which is that they have no inherent value. That a human being is only worth as much as they can earn. He argues that he earns thousands of times more than a school teacher, which makes him that much more valuable than school teachers. And people on welfare, he suggests, have no value. They have negative value. He argues, though, that cats have value—because watching them provides pleasure to people.

JW: The Mercers fund candidates, but that’s only part of their political spending. The other part is equally significant: the organization and ideological apparatus.

JM: Since 2008, between 2008 and 2016, they put $77 million into American politics. A lot of that went into building up a few organizations. They put 10 million dollars into Breitbart News. Then they built up their own political data company, called Cambridge Analytica. It claims to have a tremendous amount of information on American voters, something like 2,000 points of data on 220 million individual Americans. With that data it’s able to send out social media messages that are targeted to people, to try to push them politically in a direction. Then they founded an organization called the Government Accountability Institute. It produced the book Clinton Cash, which went a long ways towards defining Hillary Clinton as corrupt. It was the playbook, in a way, for how Trump took on Hillary Clinton.

JW: Rebekah Mercer has also made concrete contributions to the Trump White House in terms of the personnel.

JM: The Mercers very early on started working with Steve Bannon. Before Steve Bannon became Donald Trump’s political strategist, he was the political strategist for the Mercer family, starting around 2012. They were Bannon’s sponsors financially. And they brought in Kellyanne Conway.

JW: Robert Mercer has another daughter who, it turns out, is quite famous in her own right for suing Duke University. What’s that story?

JM: That would be the youngest daughter, Heather Sue. In high school, she decided she wanted to be a place kicker on the football team. She got on the team, and she was the only female on it. After high school she went to Duke University and went out for that football team, too. She got on that team as a place kicker, too, but she never got played much, and so she and her family sued the coach for gender discrimination. They won. Duke appealed, and the Mercers won yet again. They got a $2 million judgment against Duke. But the Mercers are conservatives, and the daughter said, “I’m not a feminist, I’m an equalist.”

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