Horatio Seymour (May 31, 1810 - February 12, 1886) was an American politician. He was Governor of New York in 1853-4 and 1863-4.
Seymour was a so-called War Democrat who supported the Union's military cause; however, during his second term as governor, he became a leading Northern opponent of PresidentAbraham Lincoln's administration during the American Civil War. Seymour protested Lincoln's restriction of civil liberties during the Civil War, as well as the Emancipation Proclamation and the Union's military draft. He advocated the vigorous prosecution of the war, but protested against the extensive use of war powers by Lincoln.
Seymour also ran for President in the 1868 election with Francis Preston Blair Jr. as his running mate. The ticket lost to Republican candidate Ulysses S. Grant and his running mate Schuyler Colfax by a margin of 214-80 in the electoral college.