Recently, the Supreme Court effectively abolished the right to assembly in three Southern states. By refusing to hear an appeal of a speaker accused of being liable for what a protester did in an audience the speaker addressed, the court exposed all protest organizers and speakers to potentially ruinous financial penalties for what unknown persons have done.

The right to assemble in public and complain about the government is so well-rooted in American history that it is hard to imagine our secession from Britain coming about without it. The colonists accepted it as normal and natural and when they gathered to shake their fists in the tyrant’s face — metaphorically of course, as George III was 3,000 miles away — they did so without fear of retribution.

Until now.

Now, if you organize, foment or even speak at a gathering in Louisiana, Mississippi or Texas, and some unknown person in the audience — at a time unknown, in a manner unknown and even unseen — harms another unnamed person nearby, the injured party can sue you.

This actually happened in Baton Rouge, Louisiana, where DeRay McKesson organized a rally in 2016 outside a police station to protest what he claimed were excessive uses of force by the police. Someone at the rally — not McKesson — threw a rock that hit and seriously injured a nearby police officer. The officer, whose lawyers have declined to identify, sued McKesson, even though they acknowledge that he didn’t throw the rock, didn’t advocate attacking the police and uttered no words suggesting imminent lawlessness.

The U.S. Court of Appeals for the 5th Circuit — which covers Louisiana, Mississippi and Texas — permitted the suit to move forward. McKesson asked the Supreme Court to intervene, and it declined to do so.

We have two fundamental legal issues intertwined here. The first is freedom of expression, and the second is vicarious liability.

Do expressive rights evaporate merely because someone in the audience became violent? Until a few days ago, the universal answer to that was: No.

Indeed, the courts have many times rejected the so-called heckler’s veto whereby a person adverse to the speaker causes a disruption that results in personal injury or property damage and the harmed parties sue the speaker. In those cases, the courts have held consistently that unless the speaker’s words command and produce immediate lawless behavior, the speaker is not liable for the heckler’s violence.

Vicarious liability — holding A liable for the crimes or misbehavior of B — often comes up in the First Amendment context. The modern jurisprudence has uniformly held that the right to free assembly is so integral to democracy, so well-rooted in our history, so necessary for effective free expression that it actually tolerates the violence that sometimes accompanies it. Were this not so, then hecklers would have their veto and there would be no such thing as free assembly.

The McKesson decision is ridiculous. When the Giants last beat the Patriots in the Super Bowl, two drunks had a fight in the stadium. Can they sue Tom Brady? Of course not.

In McKesson’s case, he neither advocated nor caused violence. Yet the court — abandoning the Terminiello principles — will allow an unnamed victim to sue him for what an unknown and unseen assailant did. This is a major blow to the freedom of expression. The court gave no reasons for its bizarre decision. One can hope that a jury will do the right thing; or the court, if it has this case again, will return to first principles.