An Ivy League professor -- an old-fashioned liberal who actually cares about free speech -- recently warned me about what's happening in classrooms like his.
He encourages class discussion of the great books he teaches in class -- but students are afraid to speak, not because they're afraid of the professor but because they fear each other.
Communist regimes have tried to stamp out dissent for more than a century.
Tyrants and totalitarians have always tried to sow suspicion among their subjects, turning friends, neighbors and even family members into informers against anyone who won't conform to the party line.
That's the scenario in George Orwell's dystopian classic Nineteen Eighty-Four, and it's the intention behind China's insidious "social credit" system today.
What Orwell never imagined, though, was that young men and women in a free society would one day willingly impose "political correctness" on their peers -- and use the 21st century's decentralized social media to do it.
Students, the professor told me, are afraid to be recorded on their classmates' cellphones talking about politics and political philosophy -- the subjects he teaches -- and don't want to disagree with their fellow students about anything because the person they're arguing with might belong to a "disadvantaged" group.