A campus Black Lives Matter protest against an American Civil Liberties Union speaker has provoked an internal debate over free speech on the Left.

Students shouted down an ACLU leader visiting the College of William and Mary in Virginia last week, preventing a discussion about free speech by chanting "liberalism is white supremacy" and "ACLU, you protect Hitler too!" for a full hour.

Outrage spread as video of the college Black Lives Matter chapter's disruption circulated among shocked scholars, progressive leaders, and alumni.

The demonstration — motivated by the ACLU's litigation allowing for an August rally including white supremacists in Charlottesville, Va. — reignited progressive concern about students attacking freedoms that past generations of the Left struggled to establish and expand.

Jonathan Turley, a law professor at George Washington University, wrote that suspensions would be appropriate. New York Times columnist Michelle Goldberg called it "embarrassing."

Claire Gastañaga, the shouted-down executive director of the Virginia ACLU, said "a public college like William and Mary has an obligation to protect the freedom of the speaker to speak," and college president Taylor Reveley wrote the action prevented "hard questions" and a "debate where the strength of ideas" prevails.

Watch: William and Mary students block ACLU event:

Ironically, the same auditorium stage has been the flashpoint of national free speech debates before, with left-wing students battling conservative would-be censors for the right to host a controversial event.

In 2007 and 2008, students hosted a performance called the Sex Workers Art Show featuring a plus-sized sex worker in a G-String and an antiwar stripper armed with a gun-shaped dildo. Republican state legislators objected, putting the show's fate in flux before it was allowed to proceed with pasties covering nipples and video recordings forbidden.

The college's liberal president Gene Nichol was fired shortly after the 2008 show. His removal of a cross from the college chapel and misleading the college board about the timing of a donation being withdrawn were key factors, but many saw the show as a contributing element.

Annie Brown, a former William and Mary student who helped organize the Sex Workers Art Show events, said she sympathizes with the goals of the Black Lives Matter protesters, but is concerned about the tactics that were used.

"This is a slippery slope," said Brown, a marketing professional who also fought the college administration to distribute an envelope-pushing feminist art and literary magazine called " LIPS: Expressions of Female Sexuality," which she is in the process of relaunching.

"If we continue to undermine the right of individuals to peacefully gather and share their perspectives in intelligent, well-informed conversations, we are limiting our own ability to gather information, make informed strategies for change and also limit our freedoms to speak out in the future," Brown said.

The disruption of the ACLU event in Virginia follows the February cancellation of a speech by then-Breitbart columnist Milo Yiannopoulos at the University of California at Berkeley after violence and property damage by his opponents and the shouting down in March of political scientist Charles Murray at Middlebury College — each incident attracting significant national debate, with older left-wing scholars such as Noam Chomsky and some members of Berkeley's pioneering 1960s Free Speech Movement arguing it's wrong to censor others.

The William and Mary Black Lives Matter chapter did not respond to a request for comment, but remained defiant in the face of growing condemnation Friday, posting a message to Facebook: "The right to free speech is a fundamental human right. However, speech that condones, supports or otherwise fails to explicitly condemn injustice must be directly confronted."