The Dred Scott case was a landmark Supreme Court decision in 1857 involving an enslaved man named Dred Scott. Scott sued for his freedom after living in free territories with his owner. The Court ruled that Scott, as an enslaved person, was not a citizen and therefore had no right to sue in federal court. This decision effectively denied the rights of all enslaved people and heightened tensions over slavery in the United States. The ruling also stated that the federal government could not prohibit slavery in the territories, which further inflamed the debate between pro-slavery and anti-slavery factions. The Dred Scott decision is often cited as a significant factor leading to the American Civil War.