Billionaire Robert Mercer is best known on Wall Street as the co-chief executive officer of Renaissance Technologies, the world’s most successful quant fund, which has made a staggering $55 billion since its founding. To the rest of America, he is perhaps better known as one of the key benefactors of Donald Trump, whom he and his daughter Rebekah Mercer helped get elected after pouring money into Trump’s campaign. (Trump returned the favor, in part, by pouring that campaign money back into a data-analytics firm co-owned by Rebekah, who was later named to Trump’s transition team executive committee.) The Mercers were also instrumental in the hiring of Stephen Bannon—in whose Breitbart News they invested $10 million—and spin-mistress Kellyanne Conway, both of whom secured top positions on Trump’s campaign team and now work in the West Wing.

In your average workplace in your average election year, the politics of the guys or gals running the place might be discussed privately among staff but likely wouldn’t result in a confrontation with the boss. What’s more, the mostly left-leaning employees at Renaissance have had a like-minded friend in chairman and founder Jim Simons, who has been a major donor to the Democratic Party and Hillary Clinton’s bid for the White House. But 2016 was not your average election year and Renaissance is not your average workplace. With the amount of money people are taking home, they literally have the ability to reshape America in whichever way they see fit. And for Renaissance partner and research scientist David Magerman, Mercer’s support for Trump’s anti-immigration policies and his associations with white-nationalist fellow travelers was too much to take. So he started to become a little more vocal at the office about his disdain for Mercer’s activities, which resulted in this slightly awkward interaction, dutifully reported by The Wall Street Journal:

Magerman says he was in his home office in suburban Philadelphia earlier this month when the phone rang. His boss, hedge-fund billionaire Robert Mercer, was on the line.

“I hear you’re going around saying I’m a white supremacist,” Mr. Mercer said. “That’s ridiculous.”

“Those weren’t my exact words,” Mr. Magerman said he told Mr. Mercer, stammering and then explaining his concerns about Mr. Trump’s policy positions, rhetoric and cabinet choices. “If what you’re doing is harming the country then you have to stop.”

For some, the incredibly uncomfortable nature of that phone call, not to mention the real possibility of getting fired, would have been enough to get them to back down. But Magerman is doing no such thing. In fact, he’s ramping up his efforts to show Mercer that he’s not going to stand by and let the politics of Breitbart News ruin the country. And he’s not just doing that by going on the record with the Journal and saying his boss is “using the money I helped him make to implement his worldview” that “government be shrunk down to the size of a pinhead.”

To try to counteract his boss’s activities, Mr. Magerman says he has been in touch with local Democratic leaders and plans to make major contributions to the party. He says he called Planned Parenthood to offer his assistance and contacted Jared Kushner, Mr. Trump’s son-in-law and White House adviser, to voice his concerns about Ms. Conway and Mr. Bannon. He says he failed to reach Mr. Kushner.

Perhaps most boldly, Magerman is considering cutting Mercer off at the source of his power.

Mr. Magerman has one idea that would reduce the power of people like Mr. Mercer. He said he was thinking about reaching out to Democratic Sen. Elizabeth Warren (D., Mass.) to craft proposals to reduce speculative trading, which presumably would curtail Renaissance’s profits.

Even for like-minded patriots in the financial-services industry, that might be a bridge too far.