“Fuck you, LBJ!” chanted the hippies and yippies in Chicago’s Grant Park, blocks from the 1968 Democratic Party convention. Protest has become such a homogenized art form in the years since that you can’t blame writer-director Brett Morgen for harking back to that corrosive summer, when taking a tear-gas canister to the face was a badge of honor, and policemen delivered truncheon blows the way Realtors hand out business cards. From the maelstrom of angry bodies, authorities charged seven protesters—including future entrepreneur Jerry Rubin and future Jane Fonda husband Tom Hayden—with violating the Anti-Riot Act. The ensuing trial took place off-camera, but Morgen (co-director of the entertaining Robert Evans portrait, The Kid Stays in the Picture) has ingeniously re-created the proceedings through motion-capture animation and readings of court transcripts. The technique produces moments of delicious high comedy, particularly when Judge Julius Hoffman (voiced by Roy Scheider) explodes at the antics of defense attorney William Kunstler (Liev Schreiber), or when knee-jerk meditator Allen Ginsberg (Hank Azaria) lays down a basso continuo of “Om” over a storm of legal caterwauling. Deftly spliced with newsreel footage, these sequences embody the “total theater” principle of yippie leader Abbie Hoffman, “with everybody becoming an actor.” The only trouble with such an aesthetic, in real life as in documentaries, is its almost willful obscuring of the issues at stake. Watching Morgen’s movie, you’d never know that, behind all the guerrilla stagecraft, something serious was being debated and that, through the clouds of tear gas, America was being handed over to the Republican Party. The Chicago Seven still has some ’splainin’ to do.