Final answer:
The Missouri Compromise admitted Missouri as a slave state and Maine as a free state, and closed most of the Louisiana Purchase to slavery north of the 36°30' line, making it a significant moment for antislavery advocates.
Step-by-step explanation:
The Missouri Compromise
The Missouri Compromise was an influential piece of legislation passed in 1820 that had deep implications for the future of slavery in the United States. It admitted Missouri as a slave state and Maine as a free state, preserving the balance between slave and free states in the Senate. Key to this compromise, and of particular interest to antislavery advocates, was the inclusion of what came to be known as the Thomas Proviso. This provision closed most of the Louisiana Purchase to slavery by banning it north of the 36°30' line, which was the southern boundary of Missouri, leaving future territories free of slavery. However, as significant as this may have been, it did not offer gradual emancipation of slaves in Missouri, exclude slavery from all territories north of the Ohio River and east of the Mississippi River, prohibit slavery in future territorial acquisitions, or condemn the fugitive slave law.