Updated

University of Wisconsin students who repeatedly disrupt campus speakers or presentations could be suspended or expelled under a Republican-backed bill the state Assembly debated Wednesday.

The measure, expected to be voted on late Wednesday night, is the latest salvo in the national push among some conservatives to crack down on disruptions they say is quelling free speech on liberal college campuses. Conservatives are worried that right-wing speakers aren't given equal treatment as liberal campus presenters, while other students have complained about free expression fanning hate speech.

Democrats, who didn't have the votes to stop the bill in the Assembly, blasted it as an unconstitutional attack on freedom of speech.

"It basically gags and bags the First Amendment," said Democratic Rep. Chris Taylor of Madison.

Republican backers told reporters that the bill would protect speech from those who repeatedly try to quash it.

"We have to lay down some groundwork here and we have to create a behavioral shift so everyone can be heard and has the right to express their views," said the measure's sponsor Republican Rep. Jesse Kremer.

The bill must still pass the GOP-controlled Senate and be signed by Gov. Scott Walker before becoming law.

Walker has voiced support for it.

"To me, a university should be precisely the spot where you have an open and free dialogue about all different positions," he said in an April interview with WISN-TV. "But the minute you shut down a speaker, no matter whether they are liberal or conservative or somewhere in between, I just think that's wrong."

The proposal comes in the wake of incidents on college campuses across the country in which protests or threats marred conservative presentations.

Fights broke out at New York University in February after protesters disrupted a speech by Gavin McInnes, founder of a group called "Proud Boys" and a self-described chauvinist. That same month there were protests at the University of California-Berkley ahead of an appearance by former Breitbart editor Milo Yiannopoulos. That school canceled an April speech by conservative firebrand Ann Coulter due to security concerns. And in November, UW-Madison students shouted down former Breitbart editor Ben Shapiro.

Under the Wisconsin bill, two complaints about a UW System student's conduct during a speech or presentation would trigger a hearing. Students found to have twice engaged in violence or disorderly conduct that disrupts another's freedom of expression would be suspended for a semester. A third offense would mean expulsion. UW institutions would have to remain neutral on public controversies and the Board of Regents would have to report annually to legislators about incidents.

"You're hoping to neuter the university from having any stance on things," said Democratic Rep. Cory Mason.

The bill is based on a model proposal the conservative Arizona-based Goldwater Institute put together to address campus free-speech issues. Legislation based on the model has been enacted in Colorado, with others being considered in five states, including Michigan, North Carolina and Virginia, according to the institute.

Democrats argue that the measure could open the door to partisan operatives attending speeches and filing complaints against students to get them thrown out of school.

"We are returning, when we do this, to the witch hunt era of Joe McCarthy," said Democratic Rep. Fred Kessler, referring to the former U.S. senator from Wisconsin who made it his mission in the 1950s to identify Communists.

The only group registered in support of the measure is Americans for Prosperity, a conservative advocacy organization. Opponents include a group representing faculty on the flagship UW-Madison campus, the labor union representing UW employees and the League of Women Voters.