The Missouri Compromise

Historical Background and Map

United States, 1821
Map showing the free states, states undergoing gradual abolition, free states via the Ordinance of 1787, free states via the Missouri Compromise, and slave-holding states in 1821.


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The Missouri Compromise was the first of the major compromises of the 19th century intended to ease regional tensions over the issue of slavery. While the compromise worked out on Capitol Hill accomplished its immediate goal, it only postponed the eventual crisis that would split the nation and lead to the Civil War.

In the early 1800s, the most divisive issue in the United States was slavery. Following the American Revolution, most states north of Maryland began programs of gradually outlawing slavery, and in the early decades of the 1800s, the slave-holding states were primarily those in the South. In the North, attitudes were hardening against slavery, and as time passed the passions over slavery threatened repeatedly to shatter the Union.

The Missouri Compromise of 1820 tried to resolve the question of whether slavery would be permitted in the new territories admitted as states to the Union. As part of the agreement, Maine would be admitted as a free state and Missouri as a slave state, thereby preserving the balance of slaves states and free. The Missouri Compromise also banned slavery in areas north of the 36°30′ parallel (with the exception of Missouri). The legislation was the result of the complicated and fiery debate, but once enacted it did seem to reduce tensions for a time.

The passage of the Missouri Compromise was significant as it was the first attempt to find some solution to the issue of slavery. However, it did not resolve the underlying problems. There were still slave states and free states, and the divisions over slavery would take decades, along with a bloody Civil War, to resolve.

The Missouri Crisis

The crisis that led to the Missouri Compromise began with Missouri's application for statehood in 1817. After for Louisiana itself, Missouri was the first territory from within the area of the Louisiana Purchase to apply for statehood. The leaders of the Missouri territory intended it to be a state with no restrictions on slavery, which aroused the anger of politicians in the northern states.

The “Missouri question” was a monumental issue for the young nation. When asked for his views on it, former president Thomas Jefferson wrote that "this momentous question, like a fire bell in the night, awakened and filled me with terror."

Controversy and Compromise

Congressman James Talmadge of New York sought to amend the Missouri statehood bill by adding a provision that no more slaves could be brought into Missouri. Talmadge’s amendment also proposed that the children of the slaves already in Missouri (which were estimated at about 20,000) be set free at the age of 25.

The amendment provoked an enormous controversy. The House of Representatives approved it, voting along sectional lines. However, the Senate rejected it and voted to have no restrictions on slavery in Missouri.

Meanwhile, Maine, which was to be a free state, was being blocked from joining the Union by southern senators. A compromise would eventually be worked out in the next Congress, which convened in late 1819. The Missouri Compromise dictated that Maine would enter the Union as a free state, and Missouri would enter as a slave state.

Henry Clay of Kentucky was Speaker of the House during the debates over the Missouri Compromise and was deeply engaged in moving the legislation forward. Years later, he would be known as "The Great Compromiser," in part because of his work on the landmark deal.

The Impact of the Missouri Compromise

Perhaps the most important aspect of the Missouri Compromise was the agreement that no territory north of Missouri’s southern border (the 36° 30' parallel) be allowed to enter the Union as a slave state. That part of the agreement effectively stopped slavery from spreading into the rest of the area of the Louisiana Purchase.

The Missouri Compromise, as the first great federal agreement over the slavery issue, was also important in setting the precedent that Congress could regulate slavery in new territories and states. The question of whether the federal government had the authority to regulate slavery would be hotly debated decades later, especially in the 1850s.

The Kansas-Nebraska Act

The Missouri Compromise was ultimately repealed in 1854 by the Kansas-Nebraska Act, which effectively eliminated the provision that slavery would not extend north of the 30th parallel. The legislation created the territories of Kansas and Nebraska and allowed each territory's population to determine whether or not slavery would be permitted. This led to a series of confrontations that became known as Bleeding Kansas, or the Border War. Among the anti-slavery fighters was John Brown, who would later become famous for his raid on Harpers Ferry.

The Dred Scott Decision and the Missouri Compromise

Controversy over the slavery issue continued into the 1850s. In 1857, the Supreme Court ruled on a landmark case, Dred Scott v. Sandford, which concerned an enslaved African American man named Dred Scott who had sued for his freedom on the grounds that he had lived in Illinois, where slavery was illegal. The court ruled against Scott and declared that any African American, enslaved or free, whose ancestors had been sold as slaves could not be an American citizen. Since the court decided that Scott was not a citizen, he had no right to sue. As part of its decision, the Supreme Court also declared that the federal government had no authority to regulate slavery in the federal territories. This decision, then, held that the Missouri Compromise was unconstitutional.