An excerpt from Grassroots: The Autobiography of George McGovern. On 31 March 1968, President Lyndon Johnson made the surprise announcement that he was withdrawing from the Democratic presidential primary after ekeing out a narrow 49%-42% victory over Sen. Eugene McCarthy, the anti-war candidate, earlier in the month:
Johnson’s announcement came in the context of three factors. He was about to be defeated by Gene McCarthy in the April second Wisconsin primary–with Kennedy and McCarthy preparing to challenge him in the other primaries all the way to the Chicago convention. Second, his new Secretary of Defense, Clark Clifford, had concluded that the war in Vietnam was not headed for victory. General Westmoreland was requesting at least 200,000 additional troops beyond the half million already there–with no assurance that this would turn the tide. In any event, all indications were that neither congressional nor public opinion would sustain such a major escalation. Third, Johnson viewed the gathering racial tensions and antiwar protests with deep concern, knowing that they jeopardized his presidential authority and his capacity to govern.