Causes of Sectionalism in American Histroy
The crisis solved by the compromise certainly alerted the South for the need for political unity in order to maintain its way of life in the face of a more populous North.
Likewise, it alerted both regions to the political problems inherent in westward expansion.
The Missouri Compromise did not create sectionalism, but it is important as the first possible signs of sectionalist differences in the US.
The Missouri Compromise was also important because it was successful, unlike future compromises.
The Missouri compromise was successful for a number of reasons, not just because Congress was perfectly willing to leave the question of further state admission petitions to be solved at a later date.
It also worked because neither the North nor the South could imagine territories north of the 36'30 line would desire a slavery system for reasons of land and weather patterns.
The South was willing to accept the immediate fact of Missouri's entrance into the Union rather than argue over the logistics of the “compromise.” Slavery had yet to become a matter of pride for the South, and the South had yet to feel the growing anger by radical abolitionists in the North.
The Missouri Compromise was faithfully followed for almost thirty years, until the territories the US annexed during the Mexican War once again brought up the question of congressional power to limit slavery.
There was a "forever prohibited" clause which comes up again later in the antebellum period, with the Compromise of 1850 and debates about constitutionality.
After the Missouri Compromise, Southerners became extremely suspicious concerning the expansion of federal power.
The "forever prohibited" clause was a serious statement about federal power, and if the federal government had the power to prohibit slavery in territories that had not even applied for statehood yet.
This was not agreed upon by the South and thus began the sectionalism.
Finally, the Missouri Compromise was important because it solidified the South’s insistence on the permanence and significance of the slave institution.
Southerners' rejection of the Tallmadge Proviso emphasized their position on the permanence of the slave institution as a necessary part of Southern culture.
This position would later come to cause huge problems between the two regions; the civil war.
Thus this compromise then became the beginning of American sectionalism, as it created the first cracks in the American system of government.