Free speech has suffered a lot of setbacks in recent years. College campuses are setting up “free speech zones” that limit where students can express their opinions without the risk of offending their more thin-skinned classmates. Expressing an opinion online or telling a joke that’s misinterpreted can actually get someone fired.

In the latest example, the Austin music, technology and movie festival known as South by Southwest cancelled two panels after receiving threats of violence. Members of each panel had been subjected to such threats in the past at separate events, but the previous events had stepped up security and moved ahead (including at one event that I attended).