Did the civil rights movement impact the development of the American state? Despite extensive accounts of civil rights mobilization and narratives of state-building, there has been surprisingly little research within the field of American Politics that has explicitly examined the importance and consequence that civil rights activism has had for the process of state-building in American political and constitutional development. Through a sweeping archival analysis of the NAACP’s battle against lynching and mob violence from 1909-1923, this book examines how the NAACP raised public awareness, won over American presidents, and secured the support of Congress. Finally, in the NAACP’s most far-reaching victory, the Supreme Court ruled that the constitutional rights of black defendants were violated by a white mob in the landmark criminal procedure decision Moore v. Dempsey. Civil Rights and the Making of the Modern American State hopes to contribute to a greater understanding of the “rights revolution” that would take place later in the century. The project challenges contemporary understandings and presents a re-evaluation of the criminal procedure revolution and the struggle for African American citizenship. By examining how a marginalized group was able to use the opportunities in the American political system to secure rights in the early part of the 20th century, this project demonstrates the importance of citizen agency in the making of new constitutional law and state development in a period unexplored by previous scholarship.