Clement Laird Vallandigham (July 29, 1820 – June 17, 1871) was an Ohio unionist of the Copperhead faction of anti-war, pro-Confederate Democrats during the American Civil War. He served as a U.S. representative from Ohio from 1858-1863. He grew to infamy as a sharp critic of Abraham Lincoln, and faced a military court for "uttering disloyal sentiments", and was sentenced to prison. He was then exiled to the Confederate States, where he then left and entered Canada. While in Canada, he attempted to run for the office of governor of Ohio.