Dred Scott was born a slave in Virginia in 1795. Little is known of his early years. In 1820, he was taken by his owner, Peter Blow, to Missouri, where he was later purchased by U.S. Army Surgeon Dr. John Emerson. After purchasing Scott, Emerson took him to Fort Armstrong, which was located in Illinois. Illinois, a free state, had been free as a territory under the Northwest Ordinance of 1787, and had prohibited slavery in its constitution in 1819 when it was admitted as a state.
In 1836, Emerson moved with Scott from Illinois to Fort Snelling, which was located in the Wisconsin territory (in what would become the state of Minnesota). Slavery in the Wisconsin Territory (some of which, including the location of Fort Snelling, was a part of the Louisiana Purchase) was prohibited by the United States Congress under the Missouri Compromise. During his stay at Fort Snelling, Scott married Harriet Robinson, a slave who had been acquired by Emerson at the fort.
In 1837, the Army ordered Emerson to Jefferson Barracks Military Post, south of St. Louis, Missouri. Emerson left Scott and his wife at Fort Snelling, where he leased their services out for profit. By hiring Scott out in a free state, Emerson was effectively bringing the institution of slavery into a free state, which was a direct violation of the Missouri Compromise, the Northwest Ordinance, and the Wisconsin Enabling Act.
Before the end of the year, the Army reassigned Emerson to Fort Jesup in Louisiana. There Emerson married Eliza Irene Sanford in February 1838. Emerson sent for Scott and Harriet, who proceeded to Louisiana to serve their master and his wife. While en route to Louisiana, Scott's daughter Eliza was born on a steamboat underway along the Mississippi River between Iowa and Illinois. Because Eliza was born in free territory, she was technically born as a free person under both federal and state laws. Upon entering Louisiana, the Scotts could have sued for their freedom, but did not. Finkelman suggests that in all likelihood, the Scotts would have been granted their freedom by a Louisiana court, as it had respected laws of free states that slaveholders forfeited their right to slaves if they brought them in for extended periods in a free state. This was Louisiana state precedent for more than 20 years.
Toward the end of 1838, the Army reassigned Emerson to Fort Snelling. By 1840, Emerson's wife Eliza returned to St. Louis with their slaves Scott and Harriet, while Emerson served in the Seminole War. While in St. Louis, she hired them out. In 1842, Emerson left the Army. After he died in the Iowa Territory in 1843, his widow Eliza inherited his estate, including the Scotts. For three years after Emerson's death, she continued to lease out the Scotts as hired slaves. In 1846, Scott attempted to purchase his and his family's freedom, but Eliza Irene Emerson refused, prompting Scott to resort to legal recourse.
Dred Scott v. Sandford, 60 U.S. 393 (1857), was a landmark decision by the U.S. Supreme Court in which the Court held that African Americans, whether enslaved or free, could not be American citizens and therefore had no standing to sue in federal court and that the federal government had no power to regulate slavery in the federal territories acquired after the creation of the United States. Dred Scott, an enslaved African American man who had been taken by his owners to free states and territories, attempted to sue for his freedom. In a 7–2 decision written by Chief Justice Roger B. Taney, the Court denied Scott's request. For only the second time in its history the Supreme Court ruled an Act of Congress to be unconstitutional.
Although Taney hoped that his ruling would settle the slavery question once and for all, the decision immediately spurred vehement dissent from anti-slavery elements in the North, especially Republicans. Most scholars today (as did many contemporary lawyers) consider the ruling regarding slavery in the territories to be dictum, not binding precedent. The decision would prove to be an indirect catalyst for the American Civil War. It was functionally superseded by the Civil Rights Act of 1866 and by the Fourteenth Amendment to the United States Constitution, which gave blacks full citizenship. As of 2007 it is widely regarded by scholars as the worst decision made by the United States Supreme Court.