Dred Scott v. Sanford (1857)
Dred Scott, a slave, was taken by his master from Missouri, a slave state, to Illinois, a free state, and then back to Missouri. Scott claimed his stay in Illinois made him a free man. Chief Justice Roger B. Taney, in this decision, stated that blacks were property, that they did not become free when taken into a free state, and that the Missouri Compromise, which had prohibited slavery in part of the Louisiana Territory, was therefore unconstitutional. By this decision, slavery became legal in all U.S. territories.