A national group is threatening to sue the University of Minnesota for limiting access to a popular conservative speaker, Ben Shapiro, who was barred from several large campus venues out of security concerns.

The Young America’s Foundation says the U has imposed unconstitutional restrictions on Shapiro’s scheduled Monday speech — and exiled him to what it calls the “cow campus” in St. Paul — because of his conservative views.

“Clearly they’re treating conservatives as second-class students,” Spencer Brown, a spokesman for the foundation in Reston, Va., said Wednesday.

Shapiro, a 34-year-old conservative icon who has drawn protests around the country, is scheduled to speak at 7 p.m. Monday at the St. Paul Student Center, a 400-seat venue. The university rejected requests by a student group, Students for a Conservative Voice, to reserve a larger space on the Minneapolis campus, saying the potential sites were unavailable or too difficult to safeguard.

The foundation, which helps promote and fund Shapiro’s speaking tour, accused the U of caving in to the threat of protests. The university, it wrote, is “trampling the rights of individual students to appease the demands of the intolerant majority.”

In a Feb. 20 letter, the foundation notified the U that it is ready to file suit if it doesn’t change course. “We demand that the University of Minnesota respect the First Amendment rights of all its students, regardless of viewpoint, by allowing Ben Shapiro to speak at Willey Hall,” an 800-seat venue on the Minneapolis campus, the letter said.

Brown said that free tickets for Shapiro’s speech were claimed within 24 hours and that hundreds of people are on a waiting list. “A lot of students won’t have the opportunity to hear him because the university has chosen to treat conservative students this way,” he said.

At the same time, he said Shapiro’s talk will be live-streamed on the Young America’s Foundation website and YouTube channel.

Shapiro, a former Breitbart editor who is now editor-in-chief of the Daily Wire, has been attacked by both the left and right for his views.

U officials say that they have worked closely with the student sponsors to find an appropriate venue for Shapiro. They ruled out Willey Hall, according to e-mail communications, because its “access from the skyway” complicated security measures.

“The students fully participated in the selection of the St. Paul Student Center and voiced no protest to either the University of Minnesota Police Department or the Office of Student Affairs when the site was selected,” the U said in a written statement Wednesday. “The University has maintained its commitment to free speech while protecting our students, our employees, the speaker, and our property.”

Brown dismissed the university’s argument, noting that it has routinely hosted other prominent speakers on the Minneapolis campus. “For them to say it’s unsafe for one man to speak for an hour ... is just frankly unbelievable,” he said.