Opposition to United States involvement in the Vietnam War reached a substantial scale in 1965 with demonstrations against the country's escalating role of in the war. Over the next several years, these demonstrations grew into a social movement which was incorporated into the broader counterculture of the 1960s.
Members of the peace movement within the United States at first consisted of many students, mothers, and anti-establishment youth. Opposition grew with the participation of leaders and activists of the civil rights, feminist, and Chicano movements, as well as sectors of organized labor.