Few decades in American history reverberate with as much historical reach or glow as brightly in living mythology as the 1960s. During those years Americans reanimated and reinvented the core political principles of equality and liberty but, in a primal clash that resonates more than half a century later, fiercely contested what those principles meant, and for whom. For years afterward, the decade’s appreciators considered the era to have its own “spirit,” defined by greater freedoms and a deeper, more authentic personhood, and given breath by a youthful generation’s agitation for change in nearly every dimension of national life. To its detractors in subsequent decades, the era was marked by immature radical fantasies and dangerous destabilizations of the social order, behind which lay misguided youthful enthusiasms and an overweening, indulgent federal government. We need not share either conviction to appreciate the long historical shadow cast by the decade’s clashing of left, right, and center and its profound influence over the political debates, cultural logics, and social practices of the many years that followed. The decade’s political and ideological clashes registered with such force because post–World War II American life was characterized by a society-wide embrace of antiradicalism and a prescribed normalcy. Having emerged from the war as the lone undamaged capitalist industrial power, the United States exerted enormous influence throughout the globe after 1945—so much that some historians have called the postwar years a “pax Americana.” In its own interest and in the interest of its Western allies, the United States engaged in a Cold War standoff with the Soviet Union over the fate of Europe and no less over the fate of developing countries on every continent. Fiercely anticommunist abroad and at home, U.S. elites stoked fears of the damage communism could do, whether in Eastern Europe or in a public school textbook. Americans of all sorts in the postwar years embraced potent ideologies justifying the prevailing order, whether that order was capitalist, patriarchal, racial, or heterosexual. They pursued a postwar “normalcy” defined by nuclear family domesticity and consumer capitalism in the shadow cast by the threat of communism and, after 1949, global thermonuclear war with the Soviet Union. This prevailing order was stultifying and its rupture in the 1960s is the origin point of the decade’s great dramas. The social movements of that decade drew Americans from the margins of citizenship—African Americans, Latina/o, Native Americans, women, and gay men and lesbians, among others—into epochal struggles over the withheld promise of equality. For the first time since 1861, an American war deeply split the nation, nearly destroying a major political party and intensifying a generational revolt already under way. Violence, including political assassinations at the highest level, bombings and assassinations of African Americans, bombings by left-wing groups like the Weathermen, and major urban uprisings by African Americans against police and property bathed the country in more blood. The New Deal liberalism of Presidents Franklin D. Roosevelt and Harry S. Truman reached its postwar peak in 1965 under President Lyndon Johnson’s Great Society and then retreated amid acrimony and backlash, as a new conservative politics gained traction. All this took place in the context of a “global 1960s,” in which societies in Western and Eastern Europe, Latin America, Africa, and elsewhere experienced similar generational rebellions, quests for meaningful democracy, and disillusionment with American global hegemony. From the first year of the decade to the last, the 1960s were a watershed era that marked the definitive end of a “postwar America” defined by easy Cold War dualities, presumptions of national innocence, and political calcification. To explain the foregoing, this essay is organized in five sections. First comes a broad overview of the decade, highlighting some of its indelible moments and seminal political events. The next four sections correspond to the four signature historical developments of the 1960s. Discussed first is the collapse of the political consensus that predominated in national life following World War II. We can call this consensus “Vital Center liberalism,” after the title of a 1949 book by Arthur Schlesinger Jr., or “Cold War liberalism.” Its assault from both the New Left and the New Right is one of the defining stories of the 1960s. Second is the resurgence, after a decades-long interregnum dating to Reconstruction, of African American political agency. The black freedom struggle of the 1960s was far more than a social movement for civil rights. To shape the conditions of national life and the content of public debate in ways impossible under Jim Crow, black American called for nothing less than a spiritual and political renewal of the country. Third, and following from the latter, is the emergence within the American liberal tradition of a new emphasis on expanding individual rights and ending invidious discrimination. Forged in conjunction with the black freedom movement by women, Latino/as, Asian Americans, Native Americans, and homophiles (as early gay rights activists were called) and gay liberationists, this new emphasis profoundly changed American law and set the terms of political debate for the next half century. Fourth and lastly, the 1960s witnessed the flourishing of a broad and diverse culture of anti-authoritarianism. In art, politics, and social behavior, this anti-authoritarianism took many forms, but at its heart lay two distinct historical phenomena: an ecstatic celebration of youth, manifest in the tension between the World War II generation and the baby boom generation, and an intensification of the long-standing conflict in American life between individualism and hierarchical order. Despite the disruptions, rebellions, and challenges to authority in the decade, the political and economic elite proved remarkably resilient and preserved much of the prevailing order. This is not to discount the foregoing account of challenges to that order or to suggest that social change in the 1960s made little difference in American life. However, in grappling with this fascinating decade we are confronted with the paradox of outsized events and enormous transformations in law, ideology, and politics alongside a continuation, even an entrenchment, of traditional economic and political structures and practices.