In 1934, the year after Adolf Hitler assumed power, the American Civil Liberties Union published a pamphlet entitled Shall We Defend Free Speech for Nazis in America? The answer was an emphatic yes. If the A.C.L.U. appeased critics who “condoned the denial of rights to Nazi propagandists,” the group asked, “in what position would it be to champion the rights of others?”

This is a good question as the A.C.L.U. celebrates its centenary. For it has become increasingly clear that the organization’s once stalwart commitment to the defense of free speech has gone wobbly.