Missouri Compromise

A settlement of a dispute between slave and free states, contained in several laws passed during 1820 and 1821. Northern legislators had tried to prohibit slavery in Missouri , which was then applying for statehood. The Missouri Compromise admitted Missouri as a slave state and Maine as a free state, and prohibited slavery in territory that later became Kansas and Nebraska . In 1857, in the Dred Scott decision , the Supreme Court declared the compromise unconstitutional.