Henry Clay and the Missouri Compromise of 1820

Lesson Transcript
Instructor: Alexandra Lutz

Alexandra has taught students at every age level from pre-school through adult. She has a BSEd in English Education.

The Missouri Compromise of 1820 was a United States legislation that admitted Missouri as a slave state and Maine as a free state. The significance of the compromise was that it sought to maintain balance between slave and free states in the Union. Learn about the role Henry Clay played in the enactment of the Missouri Compromise, the effects of the legislation, and Thomas Jefferson's arguments in the debate. Updated: 08/20/2021

A Delicate Balance of Power

In 1819, there was an equal balance of free and slave states
Equal Free Slave States Map

In the early part of the 19th century, the 'Old Southwest' region of the United States - that is, the area west of the Appalachian Mountains and south of the Ohio River - expanded to include what we now call the Deep South, and few Americans questioned that this was a good thing for the nation. There was more land for growing cotton, and access to the waterways was protected. In 1812, when James Madison was president, Louisiana became a state. To avoid confusion, the land that had formerly been called the Louisiana Territory was renamed the Missouri Territory. Next in office was James Monroe, under whom Mississippi, Illinois and Alabama were added to the Union without controversy. But then, in 1819, Missouri applied for statehood, and the so-called 'Era of Good Feelings' skidded to a halt.

In 1819, the nation contained 11 free and 11 slave states, creating an even balance in the U.S. Senate. Imagine being a U.S. senator at that time. How would you feel when Missouri - which seemed to be a little more northern than southern on the map - applied to become a slave state? Your feelings, of course, might depend on your opinion of slavery. They all knew that a new slave state would tip the balance of power in favor of the South. But the state had chosen slavery for itself, and that kind of autonomy was extremely important. Did Congress even have the authority to control this kind of decision? Of course, Northerners recognized that if a new slave state were added, the new senators would vote to expand slavery into all of the unorganized Western territory, and this was totally unacceptable to those who wished to see slavery at least contained, if not abolished. Southerners could see that if they lost this battle, the Northern senators would only admit more free territory until they had enough votes to amend the Constitution and outlaw slavery completely. Obviously, making a decision on this issue would have far-reaching consequences. To say the debates were heated is an understatement.

In the Missouri Compromise, a line was drawn on the map to decide future slave and free state issues
Slavery Line Map

So why was slavery suddenly an issue when plenty of other Southern states had been added in recent years? It's never easy to pinpoint historical cause and effect, but there were a number of contributing factors. For one thing, during the two-party system of the Federalists and Democratic-Republicans, there had been politicians from both North and South in both political parties, and the nation had pressing foreign issues until 1815, so you might say they just had other things to worry about earlier. Then, in 1817, New York passed a law that gradually emancipated all of its slaves, giving momentum to the abolition movement in the North and creating some worry in the South. All of these factors probably contributed, but don't forget the human factor. Are your most pressing political concerns the same ones you had a few years ago? Then, as now, the political concerns of the electorate were constantly shifting, even when old issues were unresolved. So, back to the original question: why was slavery all of a sudden the issue in 1819? It was just time.

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  • 0:05 A Delicate Balance of Power
  • 3:23 The Missouri Compromise
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