By Jon Herskovitz

AUSTIN, Texas (Reuters) – Three University of Texas professors have filed a federal lawsuit to halt a state law that would allow holders of concealed handgun licenses to bring pistols into classrooms, saying the measure would have a devastating effect on academic discourse.

The lawsuit, filed in U.S. district court in Austin on Wednesday, comes just weeks before the law takes effect on Aug. 1. It allows license holders 21 and older to bring handguns into classrooms and buildings throughout the University of Texas system, one of the nation’s largest, with an enrollment of more than 214,000 students.

“Compelling professors at a public university to allow, without any limitation or restriction, students to carry concealed guns in their classrooms chills their First Amendment rights to academic freedom,” according to the lawsuit, whose defendants include the state’s attorney general, the school’s  president and university’s board of regents.

The professors argue that they discus controversial and emotionally laden subjects such as reproductive rights and it would be inevitable for them to pull back at important junctures because of a cloud of gun violence hanging over the classroom.

University officials said they were reviewing the lawsuit and typically do not comment on pending litigation. Earlier this year, university President Greg Fenves reluctantly approved plans for holders of concealed handguns to bring pistols into classrooms, saying he had been forced to by the Republican-backed law.

The office of Attorney General Ken Paxton, a Republican, was not immediately available for comment but has said the law protects the rights of gun owners.

Governor Greg Abbott, a Republican, has said the law could prevent mass shootings because someone with a licensed concealed weapon could confront a gunman.

The so-called “campus carry” law allows private colleges to opt out and most of the state’s best-known private universities have done so, saying the law runs counter to protecting student safety.

Eight states now have provisions allowing the carrying of concealed weapons on public post-secondary campuses, according to the National Conference of State Legislatures, which tracks state laws.

The Texas law takes effect on the 50th anniversary of one of the deadliest U.S. gun incidents on a U.S. college campus:  student Charles Whitman killed 16 people by firing from a perch atop the clock tower at the University of Texas at Austin.

(Editing by Steve Orlofsky)