In 1833, Army surgeon John Emerson purchased a slave, Dred Scott, and when Emerson moved to the Wisconsin Territory, he took Scott with him. Because of the Missouri Compromise, Wisconsin was a free territory. Emerson and the Scott family moved again back to Louisiana then to St. Louis, where Emerson died and left his slaves to his wife.

Dred Scott sued for his freedom, claiming that living in Wisconsin, where slavery was prohibited, made him essentially a free man. A Missouri Court agreed, but Emerson's widow appealed to the Missouri Supreme Court, who overturned the lower court's verdict. Scott again tried to sue, but the court said that as a descendant of slaves, he was the private property of Emerson's widow and a court couldn't take away property.

Scott had one last shot at freedom—appealing to the Supreme Court of the United States.

At first, the Supremes refused to even hear the case, because, as he was legally determined to be a slave by Missouri, Scott wasn't a citizen and only citizens could bring cases before the Court. They finally relented, but decided against Scott and upheld the Missouri Supremes' decision.

For good measure, they threw in there that, PS, the Missouri Compromise was unconstitutional. The feds had no business dictating to the states about slavery or the lack of it. So even if Wisconsin was supposed to be a free state due to the Compromise, it was an illegitimate law. Dred Scott could not catch a break.

This was only the second time that the Supreme Court declared a federal law to be unconstitutional. Savvy Shmoopers know the first time. C'mon, we'll give you a sec.

Correct: Marbury v. Madison. Extra credit all around.

Anyway, the Dred Scott case demonstrated that promises…we mean compromises…are made to be broken. Like the Missouri Compromise, Compromise of 1850, and Kansas-Nebraska Act, it was another step along the road to the secession. Slavery was an issue that just refused to go away. Not being able to be settled in the legislature, it had to be settled on the bloody battlefields of the Civil War.