Missouri Compromise, 1820 | North & South sectionalism | Free states & slave states, Maine

Summary

The presentation explains how the Missouri Compromise addressed a political crisis over slavery and statehood while revealing the growing sectional divide between North and South.

The balance of free and slave states

The balance between free and slave states became a recurring political issue. In 1790, the United States had seven free states and six slave states. As new states joined, the balance shifted or returned to parity; by 1819, there were 11 free states and 11 slave states. Because every state had equal representation in the Senate, admitting a new state could change the balance of power.

Missouri’s uncertain status

Missouri sat between North and South in geography, economy, and culture. Its fertile land could support northern food crops or a more southern agricultural model, and slavery was already present. The 1820 census recorded 10,222 enslaved people among Missouri’s 66,586 residents.

Missouri was also strategically important. The Ohio, Mississippi, and Missouri rivers connected it to major routes and western expansion, and St. Louis was described as a gateway to the West.

The Tallmadge Amendment

In 1819, Representative James Tallmadge of New York proposed ending slavery in Missouri and prohibiting further enslaved labor there. The amendment passed the House, where northern states’ larger populations gave them an advantage, but it did not resolve the deadlock in the Senate. Southern senators opposed Missouri entering as a free state, while Maine was also seeking admission as a free state.

The Missouri Compromise

Jesse Thomas of Illinois proposed pairing the two admissions: Missouri would enter as a slave state, and Maine as a free state. The agreement preserved the Senate balance at 12 free states and 12 slave states once both had joined.

The compromise also prohibited slavery in the Louisiana Purchase territory north of 36°30′ north latitude, outside Missouri, while allowing it south of that line. The presentation describes the boundary as a western counterpart to the Mason–Dixon line. Henry Clay, then Speaker of the House, is sometimes credited with the compromise, though the presentation attributes the boundary proposal to Thomas.

The law also required the return of people who had escaped enslavement to those claiming their labor or services. The presentation connects this provision to later fugitive-slave legislation.

The compromise’s legacy

Maine entered the Union in 1820 and Missouri in 1821. The 36°30′ boundary remained in effect until the Kansas–Nebraska Act of 1854. Although many people initially viewed the agreement as averting a crisis, it postponed rather than ended the conflict. Sectional divisions continued to deepen and eventually contributed to the Civil War.

Speakers and sources featured

• Unidentified narrator or presenter — delivers the presentation.
• The Gazette of the Alexandria Daily Advertiser — a February 19, 1819, newspaper report quoted on the House debate and the Tallmadge Amendment.
• Section 8 of the Missouri Compromise — quoted for its provisions on slavery in the Louisiana Purchase territory and the return of people who had escaped enslavement.