Over the past four years, SFSU historian Christopher Waldrep has tried to make sense of the meaning of the word lynching in America. Why would citizens in the old West jump into action to "string him up" when the courts didn't go far enough or more than century later Clarence Thomas call the questioning in his Supreme Court hearing a "high tech lynching"?

In his new book "The Many Faces of Judge Lynch; Extralegal Violence and Punishment in America" (Palgrave Macmillan), Waldrep traces the use and meaning of the word lynching from the colonial period to the present. He explains how lynching as a form of extralegal punishment sanctioned by the community did not alter over time but that the meaning of the word changed drastically as Americans dealt with race relations.

Waldrep, who holds the Jamie and Phyllis Pasker Endowed Chair in History at SFSU, believes that the issue of lynching came down to the question of communities having confidence in the court system.

"Can the courts be trusted to punish a dangerously guilty person or was it a time for self help? History has supplied the answer. We learned that even the most local, the most isolated neighborhood must answer to a national audience, not just to themselves," he said.

Lynching to some seemed a great social evil up to the Antebellum period but then things soon began to change, said Waldrep, whose book is believed to be one of the first comprehensive looks at lynching in America.

"After the Civil War, lynching thrived because such sentimental empathy with the victims declined. In the 20th century, another national mood swing changed the nature of racial violence," he said. "Just as politicians and pundits diagnosed Americans as increasingly socially isolated and disengaged, lynching began morphing into hate crimes. After World War II, Americans not only bowled alone, they also perpetrated their racial violence alone or in smaller groups."

Waldrep said he became interested in the rhetoric of lynching while working on a previous book, "Roots of Disorder: Race and Criminal Justice in the American South, 1817-1880." In that book, Waldrep looked at how the criminal justice system in Mississippi played a role in shaping the attitudes that encouraged vigilantism. The book earned Waldrep the McLemore Prize from the Mississippi Historical Society for the best book on a Mississippi history topic.

For his new book Waldrep spent four years carefully documenting his findings. His notes and bibliography for the book fill more than 50 pages. He scoured dozens of newspapers -- from the Vicksburg Daily Whig to the New York Times -- for any news about mobs taking the law into their own hands. Waldrep personally inspected Mississippi Supreme Court records, the Department of Justice files at the National Archives and the Southern Historical Collection at the University of North Carolina. And he traveled to Memphis to meet photographer Ernest Withers, who was part of a team of black journalists from the Chicago Defender who covered the Mississippi lynching of 14-year-old Emmett Till in 1955.