In mid-1965, President Lyndon B. Johnson (LBJ) initiated the most sweeping program of domestic reform since Franklin D. Roosevelt’s New Deal. In carrying it through, however, he would make a grave mistake. As Johnson signed new legislation advancing civil rights, reducing poverty, and establishing Medicare, he dramatically ramped up America’s military involvement in Vietnam in the mistaken belief that doing so would inoculate him politically and allow him to maintain the support necessary to win reelection and continue to pursue his program.

Johnson’s greatest sin, of course, was not mere political miscalculation. Had escalating the slaughter in Vietnam somehow helped his reelection or strengthened the Great Society, it would still have been morally indefensible. But, as it turned out, Johnson’s decision didn’t help his domestic agenda or electoral prospects either. The Democrats took a beating in the 1966 midterms, losing forty-seven seats in the House and three in the Senate — a development that empowered Republicans and Southern Dixiecrats even as Democrats retained a formal majority. By 1969, with challenges mounting and the war growing increasingly unpopular, the president himself was ultimately compelled not to seek reelection.

The war, meanwhile, sapped both needed political energy and material resources from the Great Society. When Martin Luther King Jr gave an impassioned speech in April 1967 denouncing the conflict as a “demonic, destructive suction tube” that had pulled “men and skills and money” away from human needs in America, he was not only issuing a powerful statement of moral censure but acknowledging a basic material reality.