Lawmakers in Arizona and Tennessee have passed legislation to protect free speech on public college campuses, partly in response to efforts to shut down conservative speakers.

In Arizona, for the second time in two years, legislators signed a bill protecting the First Amendment at public universities.

The bill says that schools may suspend or expel students who repeatedly have interfered with others’ ability to express themselves, according to The Daily Signal.

"A college campus is intended to be a place where ideas are freely shared, not gagged. HB 2563 protects this cornerstone of higher education — the ability of students to freely participate in the marketplace of ideas on campus," said Center for Arizona Policy President Cathi Herrod.

GOP Gov. Doug Ducey signed the legislation last week.

“We have all seen the headlines. On college campuses across the country, from Berkeley to Harvard, from Missouri to Middlebury –protests and violence have attempted to silence speech that some people just don’t want to hear,” Ducey said in his bill-signing letter.

He was referring to protests against and efforts to shut down several campus speakers, likely including Charles Murray at Middlebury College last year, as well as clashes at Berkeley.

In addition to Arizona, Tennessee passed the “Campus Free Speech Protection Act,” which went into effect on Jan. 1.

“It is the further intent of the general assembly that public institutions of higher education not stifle freedom of speech and expression by implementing vague or overbroad speech codes, establishing free speech zones, imposing unconstitutional prior restraints on speech or disinviting speakers based on the anticipated reaction of opposition to others to the content of speech” the Tennessee bill said.

While states push free-speech policies, a large number of college campuses currently have “free speech zones” that act as places for students and faculty to speak freely. These have become a topic of controversy, though, for not fully allowing university students and faculty to act on their First Amendment right.

Rutgers University in New Jersey, for instance, has various “public forum spaces” that are open for student use if the proper paperwork is approved by the university. Even after students are approved to use the spaces, there are regulations that prohibit amplified sounds.

“Student organizations that do not comply with Rutgers Public Forum Policy are subject to potential cost-associated penalties and may be referred to Student Conduct,” the policy states.