Dutch historian and author Rutger Bregman has been celebrated as something of a folk hero by many on the left since his appearance at the World Economic Forum at Davos in January. Bregman told a room full of wealthy and powerful people they should pay more in taxes, and his speech went viral. It apparently caught the attention of some on the right as well.

On Feb. 11, Bregman tweeted that he had done an interview for Tucker Carlson’s Fox show and that it had not exactly gone well. According to Bregman, Carlson himself had emailed him after the taping to tell him off. “I loved what you said at Davos, so I had high hopes for our interview,” Carlson wrote in what appeared to be a screenshot of the email. “But you turned out to be far dumber, far more dogmatic and less impressive than I expected. You’re professional academic, so I guess I shouldn’t be surprised, but it was still disappointing. Also for what it’s worth, you’re an asshole.”

The next day, Bregman tweeted at Carlson to ask why his show hadn’t aired the segment.

It wasn’t really clear what had happened until Wednesday, when NowThis published a recording of that interview. In the interview, things start off friendly with Carlson, who introduced Bregman by saying he’d “take [his hat] off” to him over his respect for his comments at Davos. “Are you the first person to ever note that people are flying private to talk about global warming and that none of them mention tax avoidance?”

“It is a bit hypocritical, isn’t it?” Bergman said.

Tucker laughed. “Yes it is, and others have noted that. We’ve noted it on our show.”

But Bergman did not let things remain chummy for long:

You know, the vast majority of Americans for years and years now according to the polls, including Fox News viewers and including Republicans, are in favor of higher taxes on the rich. Higher inheritance taxes, higher top marginal tax rates, higher wealth taxes, it’s all really mainstream. But no one’s saying that at Davos, just as no one’s saying it on Fox News, right? And I think the explanation for that is quite simple, is that most of the people in Davos, but also here on this channel, have been bought by the billionaire class. You know? You’re not meant to say these things. So I just went there, and I thought, you know what, I’m just going to say it, just as I’m saying it right here on this channel.

Carlson, who tried to steer the topic back to tax avoidance, threw off a comment that “it would be interesting to know how many hours of Fox you’ve watched.” In the exchange that followed, Bregman acknowledging that tax avoidance was an major issue but asserted that raising taxes would help the American economy.

America is still pretty much the most powerful country in the world, right? So if it really would want to, it could easily crack down tax paradises. But the thing is, you guys have brought into power a president who doesn’t even want to share his own tax returns. I mean, who knows how many billions he has hidden in the Cayman Islands or in Bermuda. So I think the issue really is one of corruption and of people being bribed, and of not being, not talking about the real issues. What the family—what the Murdochs basically want you to do is to scapegoat immigrants instead of talking about tax avoidance.

Carlson was not pleased with the answer. “And I’m taking orders from the Murdochs, that’s what you’re saying?”

“No, I mean, it doesn’t work that directly.” Bregman responded. “But I mean, you’ve been part of the Cato Institute, right? You’ve been a senior fellow there for years.”

“Well how does it work?”

“Well, it works by you taking [the Koch brothers’] dirty money. It’s as easy as that. I mean, you are a millionaire, funded by billionaires, that’s what you are. And I’m glad you now finally jumped the bandwagon of people like Bernie Sanders and AOC, but you’re not part of the solution, Mr. Carlson. You’re part of the problem, actually. … All the anchors, all the anchors of Fox—”

“You would have to be a moron, you would have to be—”

“They’re all millionaires,” Bregman said. “How is this possible? Well it’s very easy, you’re just not talking about certain things.”

Carlson then brought up a separate point of protest: “It doesn’t even—Fox doesn’t even play where you are. … You’ve never seen Fox before.”

“I have, actually. I can’t say I’m a great fan of your show, but I do my homework when you invite me on your show. So I mean, you’re probably not going to air this. … But you’re a millionaire funded by billionaires and that’s the reason you’re not talking about these issues.”

“But I am talking about these issues.”

“Yeah, only now. Come on, you jumped the bandwagon. You’re all like, oh, I’m against the globalist elite, blah blah blah. … It’s not very convincing to be honest.”

“I wanna say to you, why don’t you go f— yourself, you tiny brain—and I hope this gets picked up, because you’re a moron. I tried to give you a hearing, but you were too fucking annoying for me to—”

Bregman cut him off. “You can’t handle the criticism, can you?”