While the 1950s are stereotyped—sometimes unfairly—as a decade of quiet optimism, prosperity, and social conformity, the 1960s are often stereotyped—rather accurately—as a decade of turbulence, political activism, and growing discontent. During the course of the decade, the American military became increasingly involved in the war in Vietnam (1954–75), sparking massive protests at home. The assassination of four important American leaders, including President John F. Kennedy (1917–1963), raised fears that the United States was no longer a peaceful nation. Organized protests by women, African Americans, homosexuals, and antiwar activists challenged the American social structure.

The 1960s began with a wave of optimism as Americans elected U.S. senator John F. Kennedy of Massachusetts to the presidency. Kennedy was the youngest person and the first Catholic elected to the nation's highest office. He encouraged Americans to "Ask not what your country can do for...