Conservative commentator Ben Shapiro revised his usual bash-the-leftists script in a speech this month to a packed auditorium at Stanford University.

He still mocked the “radical left,” but on that evening, Shapiro unloaded on far-right figures who traffic in white supremacy and anti-Semitism. “Pure, unbridled, vile garbage,” he called it.

A few days later, the far right derailed a conservative event on another campus. Donald Trump Jr., son of the president, had come to the University of California at Los Angeles to promote his book “Triggered: How the Left Thrives on Hate and Wants to Silence Us.” Chanting “Q-and-A!” far-right protesters jeered organizers who apparently had decided to block questions from the audience. The event was abruptly cut short, a humbling scene for Trump Jr.

These episodes illuminated tensions within the conservative political movement as far-right activists — including followers of a 21-year-old YouTube flamethrower named Nicholas Fuentes — seek influence among young Republicans on campuses and elsewhere ahead of the 2020 presidential election.

At stake, analysts say, is how President Trump’s youngest voters define Trumpism. Will they embrace white nationalism and similar far-right causes — or reject them?

“Part of this is an internecine war within conservatism,” said Nicole Hemmer, a Columbia University scholar and author of “Messengers of the Right,” a 2016 book on conservative media. “Who is the true follower of Donald Trump? That’s the fight you’re seeing.”

Fuentes, a Boston University dropout who lives in the Chicago suburbs, has emerged as a champion of those on the right who believe mainstream conservatism — in their words, “Conservative Inc.” — has gone astray. He attended the 2017 Unite the Right rally in Charlottesville but denies he is a neo-Nazi or a white nationalist.

On his “America First” YouTube show, Fuentes espouses “demographic realism.” That means he takes the hardest line possible against immigration: “We’re slamming the door so hard that people’s faces are shattering,” Fuentes says. He also expresses fear about what will happen to America as its population becomes much less white — “dramatic and radical change,” he says, “that will come with not-insignificant consequences, and not all of them good.”

Fuentes on his Internet show denounces same-sex marriage and “transgenderism” as “deviancy,” and he questions U.S. foreign aid to Israel. In January, Fuentes likened the Holocaust to a cookie-baking operation led by the Cookie Monster in a video monologue that implied he questions the death toll of 6 million Jews.

Fuentes said in a telephone interview earlier this month with The Washington Post that the Cookie Monster video was meant to be a “lampoon.” He said he acknowledges that the Holocaust was the systematic persecution and murder of 6 million Jews by the Nazi regime and its collaborators. “I’ve never denied the Holocaust,” he said.

Fuentes said he is Catholic and that his ethnic background includes Mexican heritage through his father’s ancestors. In a video after the August shootings in El Paso that left 22 dead, including Mexicans and Mexican Americans, Fuentes declared: “The easiest way for Mexicans to not get shot and killed in Walmart is for them to not [expletive] be here.”

Asked about that statement and others, Fuentes said in an email: “I don’t feel compelled to explain every ‘shocking’ phrase I’ve uttered in the over 1,000 hours of content I’ve produced in the span of four years. It’s kind of missing the point.”

His show’s audience, Fuentes said, is “zoomers,” those born after the mid-1990s in what is known as “Generation Z.”

Michelle Malkin, a conservative blogger, expressed support for Fuentes and others “seeking answers to tough questions about where America is headed,” according to prepared remarks for a speech she gave at UCLA. Asserting that she would not disavow Fuentes, Malkin praised “the new generation of America Firsters exposing the big lies of the anti-American open borders establishment.”

She added: “If I was your mom, I’d be proud as hell.”

Reveling in the attention he has received lately, Fuentes cheers those who call themselves “Groypers” — the name of a far-right meme based on a cartoon toad — and troll prominent conservatives. Shapiro is one target. Another is Charlie Kirk, founder of the conservative student network Turning Point USA, who moderated the Nov. 10 event at UCLA with Trump Jr.

Turning Point declined to comment on Fuentes.

Kirk wrote earlier this month on Twitter: “Ethno-Nationalism is Un-American. It has NO place in the conservative movement.” Trump Jr. retweeted another Kirk statement denouncing white supremacists who came to a Turning Point event.

Fuentes said he supports the president and Trump Jr. but not Kirk.

Shapiro tore into Fuentes in his Nov. 7 speech at Stanford, without mentioning him by name. “You tell edgy jokes about the Holocaust and cookies,” Shapiro said. “Because, I mean, what could be funnier than that, obviously?”

Shapiro ridiculed certain fringe figures of the right wing: “They rant, or they cry or they even sing their white-supremacist anti-Semitic moon-landing conspiracism into their webcams for hours at a time while insisting they don’t care about attention. But of course that’s exactly what they care about the very, very most.”

Afterward, the Stanford College Republicans wrote on Facebook: “We were delighted to see Ben Shapiro take a sledgehammer to the so-called ‘alt-right’ during his campus lecture here at Stanford. Ben Shapiro beautifully revealed how the alt-right is just as antithetical to true conservatism as the left.”

“Alternative right” refers to a small far-right movement that seeks a whites-only state. It appears that fewer people identify with the term since the deadly Charlottesville rally cast a spotlight on alt-right and neo-Nazi demonstrators.

Thomas J. Main, a professor of public and international affairs at Baruch College and author of a book on the alt-right, said the vocabulary of such fringe movements is in constant flux.

Participants tend to “put everything ironically and knowingly,” he said, “so the outsiders have difficulty knowing what’s going on.” But those participants also crave attention, especially on college campuses. When they get noticed, Main said, they say to themselves: “Hey, if I’m outraging everybody, I must be doing something right.”