From a constitutional point of view, the Missouri compromise was important as an example of the exclusion of slavery from the U.S. territory, acquired since the Northwest Settlement. Nevertheless, the compromise was deeply disappointing for both Northern And Southern Blacks, as it halted the southern progress of progressive emancipation on the southern Missouri border and legitimized slavery as a southern institution.  Most white Americans agreed that Western expansion was crucial to the health of the nation. But what should be done against slavery in the West? Even after Alabama was established in December 1819 without his government`s prohibition on slavery, Congress remained stuck on the Missouri issue. Finally, a compromise was reached. On March 3, 1820, Congress passed a law that granted Missouri Statehood as a slave state, provided that slavery was banned forever in the rest of Louisiana Purchase, north of the 36th parallel, which runs along the southern missouri border. In addition, Maine, a former massachusetts member, was admitted as a free state, which helped to maintain the balance between the northern and southern senators. The confusion over the Republican superiority generated by the merger has raised many fears in the southern states that a free state party could materialize if Congress failed to reach an agreement on Missouri and slavery and might threaten Southern domination. U.S. Secretary of State John Quincy Adams of Massachusetts suspected that the political constellation already existed for such a section party.   It was indisputable that the federalists were striving to regain some degree of political participation in national politics. However, there was no basis for the accusation that the federalists had guided Tallmadge in his anti-slavery measures, and there was no indication that a New York-based King Clinton alliance was attempting to establish an anti-slavery party on the ruins of the Republican Party.
The assertions of the southern interests of «plot-by-plot» slavery or «consolidation» as a threat to the Union have misunderstood the forces at work in the Missouri crisis. The core of opposition to slavery in Louisiana Purchase was informed by Jefferson`s egalitarian principles and not by a federalist revival.  What agreements did Congress reach, collectively seen as a compromise on Missouri? Henry Clay, a congressional leader, played a crucial role in mediating a two-part solution, known as the Missouri Compromise. First, Missouri would be admitted to the Union as a slave state, but offset by the accession of Maine, a free state that wanted to be separated from Massachusetts for a long time. Second, slavery should be excluded from all new states of Louisiana Purchase, north of The Southern Missouri border. Citizens on both sides of the controversy felt that the compromise was profoundly wrong. Yet it took more than thirty years for the Kansas-Nebraska Act of 1854 to find that new states north of the border deserved to be able to exercise their sovereignty in favour of slavery if they wished.