Clement Laird Vallandigham (1820-1871), American politician, was the foremost Peace Democrat during the Civil War. Though he sought to end the conflict and reunite the Union, he unintentionally aided the war effort by becoming a symbol of treasonous activity.

Clement Vallandigham was born in New Lisbon, Ohio, on July 29, 1820. He attended Jefferson College in Canonsburg, Pa., and then studied and practiced law. In 1845 he was elected as a Democrat to the Ohio Legislature, where he was a proponent of limited government and noninterference with slavery. Elected to the U.S. Congress in 1856, he became noted for his harsh denunciations of the Republican party's antislavery stance. He strongly backed compromise with the South during the secession crisis of 1860-1861.

When the Southern Democrats left the party in 1861, and with the death of Stephen A. Douglas, Vallandigham became a major Democratic spokesman in Congress. Even after the Civil War erupted...