All history is the history of longing. The details of policy; the migration of peoples; the abstractions that nations kill and die for, including the abstraction of “the nation” itself—all can be ultimately traced to the viscera of human desire. Human beings have wanted innumerable, often contradictory things—security and dignity, power and domination, sheer excitement and mere survival, unconditional love and eternal salvation—and those desires have animated public life. The political has always been the personal.
Yet circumstances alter cases. At crucial historical moments, personal longings become particularly influential in political life; private emotions and public policy resonate with special force, creating seismic changes. This is what happened in the United States between the Civil War and World War I. During those decades, widespread yearnings for regeneration—for rebirth that was variously spiritual, moral, and physical—penetrated public life, inspiring movements and policies that formed the foundation for American society in the twentieth century.
— Jackson Lears, Rebirth of a Nation: The Making of Modern America, 1877-1920