Writing for the Court, Chief Justice Roger Taney first addressed whether Dred Scott, being of African descent, could be considered a citizen of the United States, which would entitle him to sue in federal court. Taney held Scott could not be a citizen under the Constitution, arguing that at the time the Constitution was framed, African Americans were not considered part of the political community and were excluded from the rights and privileges of citizenship. He emphasized that the framers viewed African Americans as inferior, stating, “[t]hey had for more than a century been regarded as beings of an inferior order… and so far inferior, that they had no rights which the white man was bound to respect.” Reviewing the historical context, Taney noted that laws in both Northern and Southern states supported the view that African Americans were not intended to be included as citizens. He pointed to laws prohibiting interracial marriage and restricting the rights of free Blacks, demonstrating that the sentiment of the time was to maintain a strict racial hierarchy.

Taney also discussed whether Congress had the authority to prohibit slavery in the territories and specifically scrutinized the Missouri Compromise, which restricted slavery in Northern territories. He concluded that such an act was unconstitutional, as it violated property rights protected by the Fifth Amendment, reasoning that, “[a]n act of Congress which deprives a citizen of his liberty or property, merely because he came himself or brought his property into a particular Territory of the United States, and who had committed no offense against the laws, could hardly be dignified with the name of due process of law.” Taney asserted that slaves were property and that the government was obligated to protect property rights. He argued that the Missouri Compromise, by excluding slavery from certain territories, unlawfully deprived slave owners of their property without due process.

Taney ultimately concluded that Dred Scott remained a slave and that neither Scott nor any other person of African descent could claim U.S. citizenship. This decision invalidated the Missouri Compromise, intensified tensions between the north and south, and moved the nation closer to civil war.