Peace activism in the United States between 1945 and the 2010s focused mostly on opposition to U.S. foreign policy, efforts to strengthen and foster international cooperation, and support for nuclear nonproliferation and arms control. The onset of the Cold War between the United States and the Soviet Union marginalized a reviving postwar American peace movement emerging from concerns about atomic and nuclear power and worldwide nationalist politics that everywhere seemed to foster conflict, not peace. Still, peace activism continued to evolve in dynamic ways and to influence domestic politics and international relations. Most significantly, peace activists pioneered the use of Gandhian nonviolence in the United States and provided critical assistance to the African American civil rights movement, led the postwar antinuclear campaign, played a major role in the movement against the war in Vietnam, helped to move the liberal establishment (briefly) toward a more dovish foreign policy in the early 1970s, and helped to shape the political culture of American radicalism. Despite these achievements, the peace movement never regained the political legitimacy and prestige it held in the years before World War II, and it struggled with internal divisions about ideology, priorities, and tactics. Peace activist histories in the 20th century tended to emphasize organizational or biographical approaches that sometimes carried hagiographic overtones. More recently, historians have applied the methods of cultural history, examining the role of religion, gender, and race in structuring peace activism. The transnational and global turn in the historical discipline has also begun to make inroads in peace scholarship. These are promising new directions because they situate peace activism within larger historical and cultural developments and relate peace history to broader historiographical debates and trends.
Spanning countries across the globe, the antinuclear movement was the combined effort of millions of people to challenge the superpowers’ reliance on nuclear weapons during the Cold War. Encompassing an array of tactics, from radical dissent to public protest to opposition within the government, this movement succeeded in constraining the arms race and helping to make the use of nuclear weapons politically unacceptable. Antinuclear activists were critical to the establishment of arms control treaties, although they failed to achieve the abolition of nuclear weapons, as anticommunists, national security officials, and proponents of nuclear deterrence within the United States and Soviet Union actively opposed the movement. Opposition to nuclear weapons evolved in tandem with the Cold War and the arms race, leading to a rapid decline in antinuclear activism after the Cold War ended.