Still, after Charlottesville, the organization has been evaluating its criteria for accepting new free speech cases, Mr. Romero said.

One issue is how the A.C.L.U. should evaluate the potential for violence when representing groups seeking to hold demonstrations. “How do we balance a concern for public safety with freedom of speech?” Mr. Romero asked. Another question under consideration, he said, relates to how the A.C.L.U. should evaluate the credibility of organizers pledging a peaceful demonstration.

Mr. Romero also indicated that the organization is not inclined to represent groups seeking to hold armed rallies. This, he said, was not “a change in approach,” but a principle the A.C.L.U. espoused as far back as 1934.

An A.C.L.U. pamphlet issued that year defended the right of Nazis to hold meetings. But the pamphlet laid out the A.C.L.U.’s opposition to permitting Nazis to engage in “drilling with arms” — that is, wielding them in public.

Fascism was then ascendant in Europe. In Germany, the Nazis’ rise to power had started in the streets, with marches, brawls, and mass demonstrations. Still, the A.C.L.U. backed the right of Nazis to march in the United States — an important point of reference, Mr. Romero said, for the A.C.L.U. as it responds to an emboldened white supremacist movement that often calls itself “the alt-right.”

“That’s a better analogue than Skokie,” Mr. Romero said, noting that the A.C.L.U.’s famous defense of the right of neo-Nazis to march, against significant opposition, in that Chicago suburb came at a time when Nazi marchers were sometimes outnumbered 70 to 1 by counter-protesters, and dependent on the police for protection.

“The issue in Skokie was the threat of violence by people who would be so moved by anger they would attack the Nazis,” said Mr. Simon, today the executive director of the A.C.L.U. in Florida. “That’s not Charlottesville.”