Pennsylvania State University's president is getting a raft of criticism from lawmakers angry over an on-campus appearance by a co-founder of the violent anti-war group the Weather Underground.

Four members of the Senate Appropriations Committee grilled university president Eric Barron at a budget hearing Tuesday about the appearance of William Ayers at programs at the Penn State Dickinson Law School this month.

Ayers spoke about democracy and diversity. The now-defunct Weather Underground opposed the Vietnam War and claimed responsibility for several bombings.

Republican Sens. John Eichelberger and Kim Ward want to know how the university can stop appearances by people whose actions are offensive.

Barron says he's sympathetic but his hands are tied because the event was sponsored and financed by student groups. He says the ban on such interference was upheld by the U.S. Supreme Court.