In 1846 a slave named Dred Scott and his wife, Harriet, sued for their freedom in a St. Louis city court. The odds were in their favor. They had lived with their owner, an army surgeon, at Fort Snelling, then in the free Territory of Wisconsin. The Scotts' freedom could be established on the grounds that they had been held in bondage for extended periods in a free territory and were then returned to a slave state. Courts had ruled this way in the past. However, what appeared to be a straightforward lawsuit between two private parties became an 11-year legal struggle that culminated in one of the most notorious decisions ever issued by the United States Supreme Court.

On its way to the Supreme Court, the Dred Scott case grew in scope and significance as slavery became the single most explosive issue in American politics. By the time the case reached the high court, it had come to have enormous political implications for the entire nation.

On March 6, 1857, Chief Justice Roger B. Taney read the majority opinion of the Court, which stated that slaves were not citizens of the United States and, therefore, could not expect any protection from the Federal Government or the courts. The opinion also stated that Congress had no authority to ban slavery from a Federal territory. This decision moved the nation a step closer to Civil War.

The decision of Scott v. Sanford, considered by legal scholars to be the worst ever rendered by the Supreme Court, was overturned by the 13th and 14th amendments to the Constitution, which abolished slavery and declared all persons born in the United States to be citizens of the United States.