The Missouri Compromise

First Great 19th Century Compromise Over Volatile Issue of Slavery

Engraved portrait of Henry Clay

by Robert McNamara | ThoughtCo.

The Missouri Compromise was the first of the major compromises of the 19th century intended to ease regional tensions over the issue of slavery. The compromise worked out on Capitol Hill accomplished its immediate goal, but 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 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 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, in 1820, was a measure hammered out in Congress to find a way to determine whether slavery would be legal in new territories admitted as states to the Union. It was the result of complicated and fiery debates, but once enacted the compromise did seem to reduce tension 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. But, of course, it did not remove the underlying problems.

There were still slave states and free states, and the divisions over slavery would take decades, and a bloody Civil War, to resolve.


The crisis developed when Missouri applied for statehood in 1817. Except 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 to the young nation. A former president, Thomas Jefferson, when asked his views on it, wrote in a letter in April 1820, “This momentous question, like a fire bell in the night, awakened and filled me with terror.”


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. Furthermore, Talmadge’s amendment also proposed that the children of the slaves already in Missouri (which were estimated at about 20,000) would be set free at the age of 25.

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

At the same time, the statehood of Maine, which was to be a free state, was being blocked by southern Senators. And a compromise was worked out in the next Congress, which convened in late 1819. The compromise held 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 he 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 Missouri Compromise.​


Perhaps the more important aspect of the Missouri Compromise was the agreement that no territory to the north of Missouri’s southern border (the 36° 30′ parallel) could enter the Union as a slave state.

That part of the compromise effectively stopped slavery from spreading into the rest of the Louisiana Purchase.

The Missouri Compromise, as the first great Congressional compromise over the slavery issue, was also important as it set a precedent that Congress could regulate slavery in new territories and states. And that very issue would become a very important topic for debate decades later, especially in the 1850s.

The Missouri Compromise was ultimately repealed in 1854 by the Kansas-Nebraska Act, which eliminated the provision that slavery would not extend north of the 30th parallel.

While the Missouri Compromise seemed to settle an issue at the time, its full impact still lay years in the future. The issue of slavery was far from settled, and further compromises and Supreme Court decisions would play a role in the great debates over it.

And while Thomas Jefferson, writing in retirement in 1820, had feared the Missouri Crisis would shatter the Union, his fears were not fully realized for another four decades, when the Civil War erupted and the slavery issue was ultimately settled.

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