During the early nineteenth century, the sectional lines between the free north and the slave south were being gradually drawn. Slavery began to gain prominence as a national issue, and the South became solidly united behind the institution of slavery as it became more critical to their economic success. By 1819, the United States was comprised of an equal number of free and slave states—11 of each.

In 1812, Louisiana had entered the Union, and the balance of the Louisiana Purchase was organized into the Missouri Territory. As the population trickled westward, many Southerners and their slaves settled the region north and west of St. Louis. In 1819, the settlers petitioned the House of Representatives for admission of the state of Missouri as a slave state, since the population exceeded the required 60,000. Missouri was the first area west of the Mississippi to apply for statehood that was entirely part of the Louisiana Purchase.

Missouri’s petition became another sectional issue and led to the end of the “Era of Good Feelings.” Northerners opposed adding Missouri as a slave state because it would upset the current balance of free and slave states. During the debate over Missouri’s admission, Congressman James Tallmadge of New York introduced an amendment stating that no more slaves could be brought into Missouri and that all slaves born in Missouri after the territory became a state would be freed at the age of 25.

Southerners were extremely concerned about the Missouri emancipation amendment and felt the future of the slave system might depend on it being vetoed. They were aware that the amendment could set a damaging precedent for all of the Louisiana Purchase and any land west of the Mississippi. They also held concerns that if Congress abolished slavery in Missouri, they could attempt to do likewise in all of the southern states.

Population growth in the north had led to a majority for the northern states in the House of Representatives. However, because the Senate had equal representation from each state and there was an equal number of free and slave states, the Senate was split on the issue. The House of Representatives passed the Tallmadge Amendment on a strictly sectional vote, but the Senate rejected it, with some Northern Federalists joining the South to spite the Republicans.

Congress was deadlocked for some time over admission of Missouri as a slave state. The primary issues were political and economic balance. Northerners were concerned that Missouri—and any other new slave states—would be over-represented in Congress based on the Three-Fifths Compromise, which said 60 percent of slaves were counted in determining a state’s delegation to the House of Representatives. A secondary issue that was voiced by Northerner abolitionists was the moral question of slavery. However, the morality of slavery did not influence the solution to the problem at hand.

Henry Clay of Kentucky played a leading role in developing what would be called the “Missouri Compromise.” Missouri was admitted as a slave state, and Maine was separated from Massachusetts and admitted as a free state. This compromise preserved the balance between northern and southern states, as well as free and slave states. In addition, Congress prohibited slavery in all other parts of the Louisianan Purchase north of the line of 36° 30’—the southern boundary of Missouri. This second part of the Compromise was rather ironic, considering Missouri was north of the designated no slavery line.

The Missouri Compromise lasted for 34 years. Both sides had yielded something in the compromise, but both felt they had gained something as well. Northerners were satisfied with the compromise because it kept the balance in the Senate between free and slave states. Southerners felt they won a victory with the Missouri Compromise because at that time most Americans felt it was unlikely that the area north and west of Missouri would ever be settled.

While the controversy had subsided for the time, many Americans were beginning to see the South’s “peculiar institution” as an issue that would eventually have to be confronted. The Missouri Compromise avoided the slavery question, but it did not resolve it.

Copyright 2006 The Regents of the University of California and Monterey Institute for Technology and Education