On 16 June 1966, at the Zion Baptist Church in Los Angeles, Reverend Martin Luther King gave a simple, brief speech. It took as its theme the resonant line of the folk song central that had become central to the soundtrack of the civil rights movement in the United States: We Shall Overcome. But Dr. King does not just exhort the hopeful prediction of triumph; he explains why social justice is inevitable: “We shall overcome because the moral arc of the universe is long, but it bends toward justice.”