As casualties mounted and American bombs poured down on North and South Vietnam, the Cold War foreign policy consensus began to unravel. By 1968, the war had sidetracked much of the Great Society and had tom families, universities, and the Democratic Party apart. With the entire political leadership, liberal no less than conservative, committed to the war for most of the 1960s, young activists lost all confidence in “the system.”

A massive 1969 antiwar demonstration on the Mall in Washington.
Opposition to the war became the organizing theme that united people with all kinds of doubts and discontents. “We recoil with horror,” said a SNCC position paper, “at the inconsistency of a supposedly ‘free’ society where responsibility to freedom is equated with the responsibility to lend oneself to military aggression.” With college students exempted from the draft, the burden of fighting fell on the working class and the poor. In 1967, Martin Luther King Jr. condemned the administration’s Vietnam policy as an unconscionable use of violence and for draining resources from needs at home. At this point, King was the most prominent American to speak out against the war.
As for SDS, the war seemed the opposite of participatory democracy, since American involvement had come through secret commitments and decisions made by political elites, with no real public debate. In April 1965, SDS invited opponents of American policy in Vietnam to assemble in Washington, D.C. The turnout of 25,000 amazed the organizers, offering the first hint that the antiwar movement would soon enjoy a mass constituency. At the next antiwar rally, in November 1965, SDS leader Carl Ogelsby openly challenged the foundations of Cold War thinking. He linked Vietnam to a critique of American interventions in Guatemala and Iran, support for South African apartheid, and Johnson’s dispatch of troops to the Dominican Republic, all rooted in obsessive anticommunism. Some might feel, Ogelsby concluded, “that I sound mighty anti-American. To these, I say: ‘Don’t blame me for that. Blame those who mouthed my liberal values and broke my American heart.’” The speech, observed one reporter, marked a “declaration of independence” for the New Left.
By 1967, young men were burning their draft cards or fleeing to Canada to avoid fighting in what they considered an unjust war. In October of that year, 100,000 antiwar protestors assembled at the Lincoln Memorial in Washington, D.C. Many marched across the Potomac River to the Pentagon, where photographers captured them placing flowers in the rifle barrels of soldiers guarding the nerve center of the American military.