The most important thing I teach my students is to seek out people who disagree with them. That’s because the essence of learning is testing one’s ideas, assumptions and values. And what better place to test ideas, assumptions and values than at a university? Apparently, Columbia University’s president, Minouche Shafik, does not share my view. Last week she prostrated herself before House Republicans, promising that she would discipline professors and students for protesting the ongoing slaughter in Gaza in which some 34,000 people have died, most of them women and children. The following day she summoned the New York police...