No shots were fired in the Charlottesville violence, but with more alt-right rallies planned the danger that these militia members’ loaded weapons might be used increases. The armed groups mostly back up right-wing protests, although there was one militia in Charlottesville claiming to protect peaceful counterdemonstrators at a church. (The protest also drew “antifa” — anti-fascist — counterprotesters on the political left, ready to brawl with fists and sticks against those on the other side.)

Police officials have warned that gun-packing vigilantes only compound the risks in confrontations. Charlottesville officials, citing public safety, had sought to move the protest to a different site but were rebuffed in federal court. The American Civil Liberties Union defended the protesters’ free speech rights, though lawyers concede that the issue is becoming more complex as the potential for violence grows. Some critics think that the intrusive militias in Charlottesville could have contributed to the initial hesitation by the police to break up the violence.

The critical question is how to protect peoples’ free speech in the presence of armed opponents. The gun lobby has worked to pass laws in Virginia and other states to prevent local governments from passing restrictions on open carry. But legal researchers point to elements in state laws and Supreme Court decisions saying that the right to bear arms in public is not absolute and must stop short of inducing fear in others. No help should be expected, of course, from President Trump, who was the National Rifle Association’s candidate last year. Ideally, the president should be the first to call for a ban on gun toting at public forums and tighter regulations of the adapted battlefield rifles that the gun industry markets to macho civilians.

The Southern Poverty Law Center has successfully challenged armed groups run by Ku Klux Klan chapters, emphasizing state power to control militias. Lawyers note that the Virginia Constitution says militias must be “under strict subordination to, and governed by, the civil power.”

Enforcement of this civil power seemed unfortunately lacking in Charlottesville as the militias marched into town. Now that the nation has had a sobering look at the risks they present, far more must be done to rein them in. Otherwise, the right to free speech becomes subservient to gun zealots.