It’s not an unfamiliar tableau these days: people gathered on a grassy expanse of the National Mall here, listening to someone deliver an impassioned antiwar speech with phrases like “aggressive, activist foreign policy,” “the war we are creating,” “vigorous governmental efforts to control information” and “distorted or downright dishonest documents.” At some point, the crowd breaks into applause and a young woman yells out, “That’s right!”...

The firebrand orator was Max Bunzel, a 23-year-old actor from New York, juggling the role between movie auditions — for a fee, although he said that the speech, originally delivered by Paul Potter, the president of Students for a Democratic Society, during the 1965 march on Washington, genuinely moved and affected him. Most of the college-age spectators gathered there in a clutch were fully aware they were witnessing art, but by the end they also seemed not to be simply playing along but to be genuinely engaged by Mr. Potter’s arguments.

Mark Tribe, an artist and assistant professor of modern culture and media studies at Brown University, has organized a series of such re-enactments at sites where important speeches of the New Left originally took place, and he says his intention was precisely to create such a strange cultural and political straddle. The goal was to use the speeches not just as historical ready-mades or conceptual-art explorations of context, he said, but also maybe as a genuine form of protest, to point out with the help of art how much has changed, yet how much remains the same.