American political development (APD) is a core subfield in American political science, and focuses on political and policy history. For a variety of reasons, most of the focus in the twentieth century APD has been on liberal policymaking. Yet since the 1970s, conservatives have gradually assumed control over numerous federal policymaking institutions. This edited book will be the first to offer a comprehensive overview of the impact of conservatism on twentieth century American political development, locating its origins in the New Deal and then focusing on how conservatives acted within government once they began to achieve power in the late 1960s. The book is divided into three eras, and in each it focuses on three core issues: social security, the environment, and education. Throughout, the authors emphasize the ironic role of conservatism in the expansion of the American state. Scholars of the state have long focuses on liberalism because liberals were the architects of state expansion. However, as conservatives increased their presence in the federal apparatus, they were frequently co-opted into maintaining of even expanding public fiscal and regulatory power. At times, conservatives also came to accept the existence of the liberal state, but attempted to use it to achieve conservative policy ends. Despite conservatives’ power in the US politics and governance, the American state remains gargantuan. As Conservatism and American Political Development shows, the new right has not only helped shape the state, but has been shaped by it as well.