Just before Thanksgiving, Rush Limbaugh unwittingly gave white supremacists an early Christmas present.

It began innocently enough, when Limbaugh opened the phone lines for callers. The first call came from a person who identified himself as Roy from Gurnee, Illinois. The caller began by telling Limbaugh about burgeoning excitement among right-wing youth in Europe—and then started promoting the white supremacist alt right movement. As the caller talked, the radio host nodded along, expressing pleasure with the caller’s analysis of the alt right and inadvertently lending legitimacy to that movement—which flirts with neo-Nazism.

“What I’m interested in, is all this stuff about conservatives being older people,” said the caller. “But I think that’s gonna quickly change. I think there’s a group of younger people called ‘the alt right.’ And it started in the last few years in Europe because of the Muslim invasion. And I think it’s... They’re beginning to get people over here, youngsters between 18, 25, 26, to convert to what they call ‘the alt right.’ I think it’s gonna be pretty intense. I think you should keep an eye out for it.”

Limbaugh sounded pleased.

“Yeah, that’s a good thought,” he replied. “‘The alt right,’ like in alternative right?”

“Alternative right,” replied Roy from Gurnee.

“Yeah, like in alternative media and so forth,” Limbaugh replied.

Then Limbaugh complained about liberals’ assumptions that all conservatives are old.

“In fact, we don’t have to wait for this alt whatever it is in Europe,” the host continued. “There is a thriving youthful conservative emergence happening in this country. They may be borrowing from what’s going on in Europe. But, Roy, there’s no question you’re right.”

At the least, Roy was strategic; he got America’s most-listened-to talk radio host to obliviously thumbs-up a white supremacist movement. What Roy left out of his interview is that the alt right is a neoreactionary effort comprised of right-wing agitators brought together by their opposition to immigration (in particular, Hispanic and Muslim immigration), animosity to Muslims, and general opposition to multiculturalism (they call it cultural Marxism). They hate political correctness, they like Donald Trump, and they love dubbing their enemies “cuckservatives.”

“Our enemies scream the usual ‘RACIST’, ‘WHITE SUPREMACIST’ and ‘NAZI,’” reads a post on alt right blog RamZPaul. “We just laugh and go forward.”

Limbaugh didn’t respond to a request for comment.

Marilyn Mayo, co-director of the Anti-Defamation League’s Center on Extremism, said her group keeps an eye on alt right agitating.

“It’s basically a term that white supremacists use who see themselves as part of a new movement,” she said. “They want to differentiate themselves from the conservative or mainstream right. They see the mainstream right as being opposed to white interests.”

This explains Roy from Gurnee’s concerns about a “Muslim invasion,” which could have been lifted verbatim from a site like Alternative Right. White supremacist leader Richard Spencer started that site in 2010, and it recently coined the term “muslimmivasion” to gin up fear of refugees fleeing the so-called Islamic State widely known as ISIS.

These sentiments are not confined to the bowels of internet message boards. Last week, Dutch media reported that 12 pigs’ heads were dumped near the construction site for a refugee center. NL Times reported that one of the first tweets about the incident showed pictures taken the night the heads were placed there and expressed antipathy toward refugees.

Stateside white supremacists were delighted.

“It’s good to see a creative response to the worsening Muslim invasion of Europe,” wrote author Brenda Walker at the white supremacist site VDARE. “Civic rudeness has become practically a citizen responsibility since governments have abrogated their basic responsibility of protecting the nation’s people. Specifically, if the state won’t enforce law and borders, the least citizens can do is make the hostile invaders know they are not welcome.”

That particular display also won praise from more mainstream figures on the right, including Regis Giles, who spoke on a panel at CPAC in 2011 and whose sister worked with James O’Keefe on the ACORN sting.

“This is how you separate the Muslims from the Christians in the refugee camps,” read a post on her site GirlsJustWannaHaveGuns.

It’s the same sentiment Limbaugh chin-scratched over during his pre-Thanksgiving radio show. To be clear, the radio host seemed wholly unaware of the fact that “alt right” is practically a synonym for “Neo-Nazi.” (Don’t think that’s fair? One favorite alt right site, The Right Stuff, has a vertical called “The Daily Shoah.”) But by giving the caller uncritical airtime and telling him he was unquestionably correct, he gave alt right ideas their biggest platform yet.

An earlier version of this piece misidentified Richard Spencer as Richard Taylor.