Opera, I argue in this study, foregrounds and clarifies the implications of cultural Darwinism in America at the turn of the twentieth century. While this connection may seem surprising at first glance, I explore how opera enabled Frank Norris, Gertrude Atherton, James Weldon Johnson, and Ellen Glasgow to make visible the assumptions of an imperialist foreign policy that was often based on racist assumptions gleaned from Darwinian science. Opera in these writers' novels and stories helps us interpret how cultural evolutionary theories sustained an entire system of belief based on racial hierarchy and power. This dissertation focuses on the time period 1890-1920 because it was then that Darwinian ideas were most clearly influencing America's aesthetic and political culture. In opera, the Wagner craze had reached its height and opera houses were springing up across the country to absorb enthusiastic audiences excited to hear their favorite singers and works. At the same time, America was flexing its imperialist muscle, scooping up several former Spanish colonial territories at the end of the Spanish-American War of 1898. These phenomena were fueled by the Darwinian revolution and subsequent emergence of cultural evolution. The idea that human beings emerged from more primitive life forms displaced the traditional worldview of a human-centered universe and prompted many anthropologists, ethnographers, social scientists, and writers to trace human origins and discover the roots of our instincts and impulses. This revised worldview grew into a set of beliefs about cultural evolution and the ways in which human beings develop culture and civilization. Opera, I argue, is a particularly useful field site for exploring and coming to terms with these interconnected anxieties and changes because this art form itself was considered to be the artistic expression of white civilization at its most sophisticated and fully-developed. By thinking about what it meant for opera to carry this burden, we can more fully recognize the connections between the arts, sciences, politics, and religion at the turn of the twentieth century.