Jane Shaw of the Pope Center for Higher Education Policy writes here about a disturbing trend on college campuses in which students aren’t interested in discussing and debating ideas with those with whom they differ. So much for critical thinking and the marketplace of ideas.

Once again, students are rejecting on-campus speakers who don’t toe the politically correct line. At Brown University on October 29, a group of students shouted, chanted, and booed as New York police commissioner Ray Kelly began a lecture on “proactive policing,” which includes the controversial policy of “stop and frisk.” Kelly was unable to continue. The speech was called off 27 minutes after it was supposed to begin, the Providence Journal wrote, and Kelly left the stage without comment.

The day before, students at Duke University walked out on the social scientist Charles Murray, who was there to speak on his latest book,Coming Apart: The State of White America, 1960-2010.

The event at Brown made national news, but in some ways it was less disturbing than the action at Duke. After all, the response from Brown‘s president, Christina Paxson, was appropriate. She roundly condemned the students and created a committee to investigate (whether the students will be punished remains to be seen, however). An article in Inside Higher Ed cited only one comment in favor of their actions, by an alumnus who called them “civil disobedience.”

The Brown protesters were just bullies and got no respect.

The incident at Duke—silently walking out on a speaker—fell short of the insult (and violation of free expression) of halting a speech. Charles Murray was able to speak. Yet Duke’s event was preceded by several days of discussion in the college newspaper, the Duke Chronicle. Those comments might worry Duke alumni and others who think that students ought to value the exchange of ideas—especially with someone who has been a major figure in social policy for nearly thirty years.