As the 1850s proceeded, the divide between the North and Northwest and the South and Southwest widened. The bitter debates over the slave status of newly-admitted states, which had been going on since at least the Missouri Compromise of 1820, were signs of the very real fear Southerners had of having their voice in Congress drowned out by “Yankee industrialists.” Incidents such as the Southern protests against the “Tariff of Abominations” in the 1820s and the Nullification Crisis of the 1830s demonstrated how deep a rift the tariff controversy was creating between North and South.
In Congress, Southern Representatives and Senators were concerned that their interests would not be suitably addressed. As immigrants flocked to the Northern areas, swelling the ranks, Southerners were afraid the Northern states would increase their representation in the House of Representatives, blocking “Southern-friendly” legislation. The interests of Southern Americans who were African Americans, however, did not seem to concern a large number of Southern Congressmen. By the late 1850s, the fear of Northern domination in national economic policy, combined with the desire to maintain Southern institutions (including slavery), became a major influence on the people who eventually chose to secede from the Union.