Grant's Enforcer offers a gripping story of the early years after the Civil War and the campaign led by President Grant's attorney general Amos T. Akerman to destroy the Ku Klux Klan. Akerman, a former Georgia slaveholder and the only Southerner to serve in a Reconstruction cabinet, was the first federal lawman to propose using the Fourteenth Amendment to prosecute civil rights violations.

In 1871 Akerman and his allies brought the KKK to trial in South Carolina, choosing York County as their principal target. They believed that if they could break the Ku Klux in one small corner of the former Confederacy, they could break it everywhere. Within six months, the prosecutions and convictions in federal court of key Klan leaders and foot soldiers effectively eradicated the Klan for half a century.

Drawing on a wealth of primary sources, Guy Gugliotta tells the story in real time through the voices of those who bravely resisted the Klan in York County and those who perpetrated its crimes, and through the fierce congressional debates in Washington, D.C., and Akerman's efforts to overcome infighting within the Grant administration. Grant's Enforcer rides with the Ku Klux on its way to a lynching, feels what it's like to be lied to, beaten, spat at, and betrayed by white neighbors you have known all your life, and exults with York's black citizens when the tormenters are finally brought to justice.

Gugliotta uses newspapers, documents, and first-person stories, including thousands of pages of testimony under oath taken by a Congressional joint committee tasked in 1871 to study the Ku Klux Klan, a breathtaking compilation of accounts by Ku Klux targets, their attackers, local and national politicians, public officials and private citizens. The result is a vivid portrait of the Reconstruction South through the career of this surprising man.