The Dred Scott decision was the culmination of the case of Dred Scott v. Sanford, one of the most controversial events preceding the Civil War. In March 1857, the Supreme Court issued its decision in that case, which had been brought before the court by Dred Scott, a slave who had lived with his owner in a free state before returning to the slave state of Missouri. Scott argued that time spent in a free state entitled him to emancipation. But the court decided that no black, free or slave, could claim U.S. citizenship, and therefore blacks were unable to petition the court for their freedom. The Dred Scott decision outraged abolitionists and heightened North-South tensions.