How did we get to this point in American politics? Drawing on insights from an unprecedented decades-long study of ordinary Americans’ political lives, this book tells the story of how, why, and when our politics fractured. Few time periods have been as defined by waves of monumental social change as the United States during the 1960s. Even today, almost sixty years later, the era is often depicted as a triumph of social progress. Yet, as Larry M. Bartels and Katherine J. Cramer show in The Politics of Social Change, it was Americans’ diverse reactions to the milestone events of the time—from the welcoming, to the fiercely resistant, to the largely oblivious—that planted the seeds of our current political turmoil. Their masterful analysis draws on a unique historical resource: the longest-running systematic tracking of individual Americans’ political attitudes and behavior ever attempted. The study began in 1965 when researchers interviewed hundreds of high school students across the country and then periodically reinterviewed them over the next three decades. Bartels and Cramer supplement this historical record with in-depth interviews with dozens of the original students, painting a detailed picture of the generation’s individual and collective political development. By tracing the responses of the Class of ’65 to major events of their political lifetimes—including the Civil Rights and Women’s Rights movements, the Vietnam War, the shifting role of religion, escalating economic inequality, immigration, and the rise of Donald Trump—Bartels and Cramer shed new light on the evolution of public opinion and the unsteady progress of American democracy.