Missouri Compromise 1820

Since the American Independence and Revolution, the issue of slavery and human bondage in the United States was used as a weapon of compromise and leverage over domestic policies by both Northern and Southern states. Slavery was integral to creating the U.S. Constitution as it strongly influenced the three-fifths compromise and the Great Compromise. As the nation expanded westward, the institution of slavery-again- became a point of contention between Northern states in favor of abolition and Southern states wanting to preserve their economic and societal practices. In the late 1810s, this issue came to a head over the admission of Missouri as a state in the Union. What was the Missouri Compromise? What did it do? Who proposed the Missouri Compromise? And what was the significance of the Missouri Compromise?

Importance of Missouri Compromise of 1820

In 1818, Missouri applied for admission to the United States 1819. Part of the requirements for admission is to have a written state constitution that ensures a republican form of government. The institution of slavery was allowed under the Missouri constitution.

Before Missouri’s application, other southern states were admitted to the United States, whose constitutions also allowed for slavery. These states were in the midst of an economic boom with the rapid expansion of the cotton industry. They thus felt slavery was necessary to maintain their financial system. These states were:

• Louisiana (1812)

• Mississippi (1817)

• Alabama (1819)

In 1819, Congressman Tallmadge of New York offered Missouri an ultimatum. Ban slavery in your state and emancipate those currently enslaved, and Congress would admit Missouri as a state. Missouri rejected this proposal, and the northern majority in the House blocked Missouri’s application to the Union.

Fig. 1 - A map of the Missouri Compromise that shows the free and slave states and the line dividing Missouri and Arkansas.

White southerners panicked. They were worried about the large influx of northern members of Congress and the open talk of stopping the use of slaves in the United States, and Congressman Tallmadge proved their fears correct. In response to show their commitment to using enslaved labor, Southern Senators flexed their power - where they held half of the seats- to withhold statehood from Maine. Maine's territory was under Massachusetts's jurisdiction since colonial times and was petitioning to separate from Massachusetts through statehood.

Under The Missouri Compromise of 1820: The Debate Over Slavery

This deadlock between Missouri versus Maine and the House versus the Senate began a heated debate over slavery. The northern representatives had a simple stance, slavery cannot and shall not be permitted to expand in influence and practice as new states enter the Union. The southerners advanced three arguments:

• They stood on the principle of “equal rights” that Congress could not impose conditions on Missouri that it had required for Louisiana, Mississippi, and Alabama.

• They stated that the Constitution guaranteed a state's rights to sovereignty concerning its internal affairs and domestic and economic institutions, such as slavery and marriage.

• They insisted that Congress had no power to take away the property rights of individual slaveholders, which emancipation would do.

The Missouri Compromise: 1820

Controversy and debate took hold of Congress for two years. Eventually, Henry Clay- a Congressman from Kentucky- put together several political agreements that would be known as the Missouri Compromise. Faced with harsh opposition to Congressman Tallmadge’s proposal, several northern representatives moved away from their anti-slavery stance to support Maine’s bid for statehood.

Fig. 2- A portrait of Henry Clay from 1848.

Clay negotiated a deal that would grant Maine statehood as a free state in 1820 and allow Missouri to join as a slave state in 1821. This agreement would preserve the balance of free states and slave states in Congress. For their support of the deal, Clay negotiated with southern delegates to accept the prohibition of slavery in the northern sections of the Louisiana territory above the 36’30 line of latitude.

Missouri Compromise Map

The map below shows the territorial growth of the United States from 1790 to 1920. The proposed state of Missouri is shown in yellow. The rest of the Louisiana Purchase's northern parts are in the Missouri Territory's green. The Missouri Compromise line is the 36’30 line of latitude, the southern border of Missouri.

Fig. 3 - A map of the United States territorial expansion from 1790 to 1920 shows the Missouri Compromise line

The Missouri Compromise 1820: Significance

One of the immediate impacts of the Missouri Compromise is that a precedent was set in the agreement to maintain the balance of free versus slave states in congress. For future admissions for statehood, Congress would move to keep the balance by admitting one free state for every slave state. This precedent would be maintained until 1854, when the debate over the legalization of slavery in new territories would violently erupt over the Kansas-Nebraska Act.

More importantly, white politicians had to preserve the union by compromising over slavery, just as they had done during the Constitutional Convention of 1787. But this time, it was much more difficult. Previously, the debate over slavery in the constitution took two months. The discussion lasted two years, and the Missouri Compromise did not have universal support from either delegation of representatives.

The fate of the western lands, enslaved peoples, and the Union itself was now irrevocably connected, raising the discussion of civil war and ending the American republic. In a letter to John Holmes, Thomas Jefferson had this to say about slavery and expansion: