It was the moment of greatest peril for then-Sen. Barack Obama’s political career. In the heat of the presidential campaign, videos surfaced of Obama’s pastor, the Rev. Jeremiah Wright, angrily denouncing whites, the U.S. government and America itself. Obama had once bragged of his closeness to Wright. Now the black nationalist preacher’s rhetoric was threatening to torpedo Obama’s campaign. The crisis reached a howling pitch in mid-April, 2008, at an ABC News debate moderated by Charlie Gibson and George Stephanopoulos. Gibson asked Obama why it had taken him so long – nearly a year since Wright’s remarks became public –...