formally Dred Scott v. Sandford
1857 ruling of the Supreme Court of the United States that made slavery legal in all U.S. territories.
Scott was a slave whose master had taken him in 1834 from a slave state (Missouri) to a free state and a free territory, then back to Missouri. Scott sued for his freedom in Missouri in 1846, claiming his residence in a free state and a free territory made him free. The opinion of Chief Justice Missouri Compromise as unconstitutional, maintaining that Congress had no power to prohibit slavery in the territories (see states' rights ). The decision, a clear victory for the South, increased Northern antislavery sentiment, strengthened the new Republican Party , and fed the sectional strife that led to war in 1861.