On July 18, 1957, the pastor of Dexter Avenue Baptist Church in Montgomery, Alabama—the Rev. Dr. Martin Luther King Jr.—gave a public prayer at Madison Square Garden as part of the long-running Billy Graham evangelistic campaign. In an earlier interview with historian Grant Wacker, I asked him about the background of this development by Graham to address racial justice through his ministry. He responded: Till then, his racial justice efforts were mostly memorable for starting to de-segregate his crusade audiences in 1953 (possibly 1952). In the context of the early 1950s, insisting that he would not tolerate segregated audiences was...