“One of the problems with defending free speech,” the celebrated author Salman Rushdie said, “is you often have to defend people that you find to be outrageous and unpleasant and disgusting.”

Those descriptions, and worse, certainly apply to the white supremacists, neo-Nazis, racists and bigots whose message has caused such turmoil over the past week in two cities, Charlottesville and Boston.

Their message may be vile. But in America, they get to say it. And letting them do so might be the smartest way to fight back.

Consider a third location: Skokie, Illinois, the Chicago suburb and residence of many Holocaust survivors where, 40 years ago, a free-speech battle erupted after Nazis planned to march through the streets.

Court battles, protests and righteous anger followed. In the end, the march was allowed, and heavy police protection was ready — but the Nazis never showed up, choosing to rally in downtown Chicago instead.

The executive director of the American Civil Liberties Union at that time wrote recently in the Chicago Sun-Times that Skokie’s lessons were clear: “In a country where free speech generally prevails, it is best to take hate speech in stride,” Aryeh Neier said. “Ignoring it sometimes works, as does overwhelming it with the peaceful expression of contrary views.”

Boston chose the latter approach, with perhaps 40,000 mostly peaceful protesters showing up to the “free speech” rally in Boston Common.

Americans of all political beliefs are struggling with these free-speech issues as “fringe groups” become more vocal — empowered by a president elected, in part, by appealing to racism and bigotry.

Justin Silverman, executive director of the New England First Amendment Coalition, is worried about the suppression of speech by those who disagree with it.

“When that speech is racist or anti-Semitic, it’s easy to accept that suppression. But we shouldn’t,” he told me.

Beware of the “hecklers’ veto,” he said. That’s what happens when a speech or rally is shut down in advance because of the fear of violent reaction.

In April, for example, a neighborhood group in Portland, Oregon, decided to cancel an annual parade after “anti-fascist” groups threatened violent protests if the local Republican Party participated.

This month, the University of Florida and Texas A&M University canceled campus appearances by the white-nationalist group National Policy Institute, headed by neo-Nazi Richard Spencer. And last spring, the University of California at Berkeley canceled a speech by conservative firebrand Ann Coulter.

Jeffrey Herbst, president of the Newseum and a former college president, sees a crisis in free expression on college campuses, which “should be bastions of free speech.”

“Today, they often seem to be the very places in American society where there is the least tolerance for controversial ideas,” he wrote recently.

Herbst worries about student attitudes and apparent lack of knowledge about the First Amendment.

“All too often, students want to carve out an exception to the right of free speech, which is not to allow speech that offends an identifiable group,” he told me. That’s not what the Constitution provides for, and far better is to allow offensive speech — and forcefully condemn it.

“Tactically, if people are opposed to Coulter’s views,” Herbst said, “the worst thing they can do is keep her from speaking. That makes her sympathetic and plays right into her hands.”

Safety, of course, is a real concern, as was obvious in Charlottesville, where a young female protester was killed.

That’s why it made sense for the ACLU to decide last week that it would no longer defend the rights of white-supremacist groups who carry firearms. And why it’s necessary for law enforcement to be far better prepared than it was in Charlottesville.

Boston police did much better, though Silverman was concerned about the huge “buffer zone” police created between the rally participants and the protesters, which kept some — including several journalists — from hearing the speakers.

Why not just forbid these demonstrations altogether? If you think that might be wise, here’s a thought experiment: Imagine a civil rights march that is shut down because officials fear a violent response from racists.

“It’s not that difficult to remember a time when rallies for equality and civil rights were considered offensive and unpopular,” Silverman said. “The First Amendment exists to protect that offensive and unpopular speech.”

And there’s not much agreement on what’s offensive. Some people, after all, want to keep Colin Kaepernick off the NFL field for not showing allegiance to the national anthem as he protests police brutality. Others cheered the firing of the Google employee who disparaged his female colleagues in a memo.

“Off with their heads” seems to be the prevailing response when we hear something that strikes us as vile.

That’s not what America stands for, as Supreme Court Justice Oliver Wendell Holmes wrote in dissenting to a decision (eventually overruled) denying citizenship to a Quaker pacifist woman who wouldn’t state that she would take up arms in defense of the United States.

“If there is any principle of the Constitution that more imperatively calls for attachment than any other,” Holmes wrote, “it is the principle of free thought — not free thought for those who agree with us but freedom for the thought that we hate.”

Margaret Sullivan is The Washington Post’s media columnist.