The Dred Scott decision, delivered by the Supreme Court in 1857, revolved around the key issue of whether an enslaved person could claim citizenship and sue for his freedom. Dred Scott, an enslaved African American, had lived in free territories and argued he should be free but the Court ruled that he was not a citizen and had no right to sue. The decision aggravated tensions between the North and South, effectively denouncing the Missouri Compromise, and intensified the national debate on slavery. This ruling had far-reaching implications and contributed to the escalation leading to the American Civil War.