In February 1819, the territory of Missouri petitioned Congress to be admitted as a state. At the time, America consisted of 11 slave and 11 free states, so the question was whether Missouri, with 10,000 slaves, should be admitted as a slave state or be forced to free its slaves before it was allowed into the fold.

Debate on the issue raged across the country. Finally, Henry Clay crafted a compromise in March 1820. Under the aptly named Missouri Compromise, Missouri was admitted as a slave state, and the territory of Maine came in as a free state, keeping a balance of 12 slave and 12 free.


The figure shows a breakdown of the slave/free arrangement created by the compromise. Congress also deemed that slavery would be excluded from any new states or territories above latitude 36 degrees, 30 minutes.

Proslavery forces grumbled that Congress had no constitutional right to say where slavery could and couldn’t occur; antislavery forces complained that the compromise was an admission that slavery was acceptable. But the compromise held for the next three decades, giving the country a little more time to seek a better solution it would not find.

“[T]his momentous question [the spread of slavery], like a fire bell in the night, awakened and filled me with terror. I considered it at once as the knell of the Union,” noted slaveholder Thomas Jefferson. “(W)e have the wolf by the ears, and we can neither hold him, nor safely let him go.”

The truth was that African Americans were discriminated against in the North, too. In most situations, they couldn’t vote, testify at trials, marry outside their race, join labor unions, live in “white” areas, or go to school. Free African Americans in the North, especially children, were also at risk of being kidnapped and taken to the South to be sold.