The spread of slavery into the Louisiana Territory was limited.
The US in the beginning was trying to balance the power between the Northern "Free" states (no slaves), and the Southern slave states. However, Missouri soon wanted to join the Union, as a pro-slavery state. This led to arguments on whether Missouri should be admitted or not. The Missouri promise allowed Missouri to join as a slave state into the Union, but, to balance the power, Maine was created to be a free state.
The spread of slavery into the Louisiana Territory was limited.
Except for Missouri, all other states created within the Louisiana Territory was to be free states.
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