Vice President Mike Pence denounced mounting attacks on freedom of speech on college campuses during his commencement speech at the University of Notre Dame, including “administration-sanctioned political correctness.”

“This university is a vanguard of freedom of expression and the free exchange of ideas at a time, sadly, when free speech and civility are waning on campuses across America,” he told the graduating class on Sunday.

“While this institution has maintained an atmosphere of civility and open debate, far too many campuses across America have become characterized by speech codes, safe zones, tone policing, administration-sanctioned political correctness — all of which amounts to nothing less than suppression of the freedom of speech,” the vice president added.

The former Indiana governor encouraged the graduates to speak up against “the increasing intolerance” toward opposing views, which he said are “destructive of learning.”

“As you, our youth, are the future, and universities, the bellwether of thought and culture, I would submit that the increasing intolerance and suppression of the time-honored tradition of free expression on our campuses jeopardizes the liberties of every American,” Pence said.

“This should not — and must not — be met with silence.”

The vice president might have left thinking he had some confirmation for his views on tolerance.

At the beginning of Pence’s address, a group of students walked out of the graduation ceremony to protest his presence, and others booed from the audience. The South Bend Tribune said about 150 students and family members took part in the walkout.