Art does have real social impact. Certainly such has been true of Louis Malle's Les Amants / The Lovers (1958), for it became involved in a case in the United States that went all the way to the Supreme Court.
Thanks to Nico Jacobellis and friends, Les Amants cracked open American lameness about nudity and "blue" language.
Because the Supeme Court's majority sided with Jacobellis and Les Amants in their 1964 ruling, movies like The Graduate, Bonnie and Clyde and Midnight Cowboy could be produced and shown within a handful of years. Books by Anaïs Nin, Henry Miller, Thomas Hardy, D. H. Lawrence, James Joyce, William S. Burroughs and so on could be widely circulated.
In sum, Les Amants led to a wide expansion of "acceptable" cultural productions.
I found several related articles about the case in the New York Times. Here's a sample of one of the early ones (November 15, 1959):
'LOVERS' FILM SEIZED
Cleveland Theatre Closed by Police -- Injunction Asked . . .
Lawyers for Nico Jacobellis, manager of the Heights Art Theatre, sought an injunction today in Common Pleas Court to allow renewed showings of the French film, "The Lovers," at the theatre. . . The police in suburban Cleveland Heights halted the showing of the movie last night and arrested Mr. Jacobellis on a charge of exhibiting an obscene film. . . The theatre was closed and the film confiscated for evidence . . .
Today's Rune: Signals.