Charles Murray writes at the American Enterprise Institute about a recent campus speech that did not result in violence.

If a nerdy, inoffensive speaker like me, lecturing on themes from Coming Apart (not a controversial book), could be shouted down at Harvard, we would be faced with a scary new normal. If not even Harvard, with all its resources, would protect free speech against the mob, then why would less exalted institutions be expected to do so? If a small minority of students gets to decide who is allowed to speak even at Harvard, what institution would hold the line?

But happily, my lecture went off without a hitch. The audience was attentive, or at least quiet. About ten minutes in, a dozen students, a few holding signs, got up and left, but they made no attempt to disrupt the lecture. There was half an hour of Q&A, with no holds barred on the questions I was asked and no holding back on my answers—just as a Q&A should be.

How did Harvard do it? First, Harvard has an impressively professional police department. Everything about the security arrangements betokened a team that does this kind of thing all time for everyone from prime ministers to visitors like me, and they know exactly how to do it right. But, crucially, Harvard also has an explicit policy about acceptable behavior in a lecture hall.

A student who disrupts will be warned. Continued disruption will result in expulsion from the hall, forcibly if necessary. And there was every reason for the students to believe that’s exactly what would happen. Some members of the Harvard Police Department, including the chief, stood quietly at the back of the hall, looking at once benevolent and completely willing to do whatever was necessary to enforce the rules.