The Dred Scott decision outlined the legal principle that African Americans, whether free or enslaved, could not be considered citizens of the United States and thus had no right to sue in federal court. Issued by the Supreme Court in 1857, the ruling exacerbated the sectional tensions between the North and the South, as it denied Congress the authority to prohibit slavery in the territories. This decision further entrenched the institution of slavery and made it more difficult for abolitionists to argue for African American rights, contributing to the escalating conflicts that would eventually lead to the Civil War.