Missouri Compromise

The legislation known as the Missouri Compromise, passed in the U.S. Congress in 1820, was designed to address the issue of whether or not new states that permitted slavery would be admitted to the Union. Signed into law by President James Monroe, the Missouri Compromise actually embodied several compromises painstakingly worked out and often hotly debated over a period of months between the congressional representatives of states where slavery was legal and those where it was not, and the most important of its provisions concerned slavery. The immediate issue was the Missouri Territory and its admission to the Union as a new state. Would it be admitted as a slave state, or should it be kept out of the Union unless it declared itself free? The larger question was how (if at all) slavery would be allowed to expand in the United States, or how it was to be restricted. Proslavery legislators would have preferred unlimited admittance of new slave states. Legislators from free states wanted no expansion of slavery; many wanted it abolished in the states where it already existed.

The Missouri Compromise was an attempt to give something to both of these deeply opposed sides. The legislation allowed Missouri to enter the Union as a slave state, thus mollifying proslavery advocates. At the same time, however, it specifically stated that the act was intended “to prohibit slavery in certain territories”—wording that brought crucial support from some free-state members of Congress. Moreover, the new law did in fact set up a sharp geographical limitation on the spread of slavery in the vast new lands of the Louisiana Purchase: Besides Missouri itself, no new slave states would be admitted from this territory north of Missouri's main southern boundary. Of course, this provision also implied that new slave states could enter from south of that line, but far more of the Louisiana Purchase lay to the north.

The Missouri Compromise contained other features indicating the lawmakers' goal of cobbling together a bill that both sides could bring themselves to vote for. For instance, it stated that all citizens of the new state were to be treated equally under its laws and that free blacks were not to be treated as slaves—provisions that appealed to free-staters. On the other hand, it appeased slave-staters by limiting voting for Missouri's constitutional convention to “free white male citizens of the United States” in the territory. Even more important to the proslavery forces, the law provided that a fugitive slave escaping into any state or territory of the United States could be “lawfully reclaimed” by his or her owner.

The new law also dealt with several matters not related to slavery. For example, considering that the Mississippi River formed most of Missouri's eastern boundary, one clause proclaimed that travel on that river and all waters leading into it would be “for ever free” to all citizens of the United States. As important as such a provision might be, however, what most Americans, then and for decades to come, debated about the Missouri Compromise of 1820 was its treatment of slavery.