Dred Scott sued John Sanford claiming he was a free citizen as he had lived above the 36'30 parallel line in Missouri where the Missouri Compromise declared slaves were free. John Sanford argued that Scott was not a U.S. citizen because he was black and therefore could not sue in federal court. The Supreme Court ruled in favor of Sanford, finding that Scott was not a citizen and the Missouri Compromise was unconstitutional, upholding slavery and property rights over slaves.