Explain why the missouri compromise was necessary and how thomas jefferson felt about it.

The Missouri Compromise was necessary because Missouri was going to become a US state, but it wasn't yet declared a free or slave state. There were already an equal number of free and slave states and congress feared the admitting Missouri as either one would upset the balance. The Missouri Compromise admitted Missouri as a slave state but said Maine would be a free state. Thomas Jefferson didn't agree with the compromise and feared it would start a conflict that would damage the Union

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From mexican american war , us gained new mexico.