The Ku Klux Klan, which celebrated historian Fergus Bordewich defines as "the first organized terrorist movement in American history," rose from the ashes of the Civil War. At its peak in the early 1870s, the Klan boasted many tens of thousands of members, no small number of them landowners, lawmen, doctors, journalists, and churchmen, as well as future governors and congressmen. And their mission was to obliterate the muscular democratic power of newly emancipated Black Americans and their white allies, often by the most horrifying means imaginable.

To repel the virulent tidal wave of violence, President Ulysses S. Grant waged a two-term battle against both armed Southern enemies of Reconstruction and Northern politicians seduced by visions of postwar conciliation, testing the limits of the federal government in determining the extent of states' rights. In this book, Bordewich transports us to the front lines, in the hamlets of the former Confederate States and in the marble corridors of Congress, reviving an unsung generation of grassroots Black leaders and key figures such as crusading Missouri senator Carl Schurz, who sacrificed the rights of Black Americans in the name of political "reform," and the ruthless former slave trader and Klan leader Nathan Bedford Forrest.

Klan War is a bold and bracing record of America's past that reveals the bloody, Reconstruction-era roots of present-day battles to protect the ballot box and stamp out resurgent white supremacist ideologies.