<P> The United States had become a nation of two distinct regions . The free states in New England, the Northeast, and the Midwest had a rapidly growing economy based on family farms, industry, mining, commerce and transportation, with a large and rapidly growing urban population . Their growth was fed by a high birth rate and large numbers of European immigrants, especially British, Irish and Germans . The South was dominated by a settled plantation system based on slavery; there was some rapid growth taking place in the Southwest (e.g., Texas), based on high birth rates and high migration from the Southeast; there was also immigration by Europeans, but in much smaller number . The heavily rural South had few cities of any size, and little manufacturing except in border areas such as St. Louis and Baltimore . Slave owners controlled politics and the economy, although about 75% of white Southern families owned no slaves . </P> <P> Overall, the Northern population was growing much more quickly than the Southern population, which made it increasingly difficult for the South to continue to influence the national government . By the time the 1860 election occurred, the heavily agricultural southern states as a group had fewer Electoral College votes than the rapidly industrializing northern states . Abraham Lincoln was able to win the 1860 Presidential election without even being on the ballot in ten Southern states . Southerners felt a loss of federal concern for Southern pro-slavery political demands, and their continued domination of the Federal government was threatened . This political calculus provided a very real basis for Southerners' worry about the relative political decline of their region due to the North growing much faster in terms of population and industrial output . </P> <P> In the interest of maintaining unity, politicians had mostly moderated opposition to slavery, resulting in numerous compromises such as the Missouri Compromise of 1820 under the presidency of James Monroe . After the Mexican--American War of 1846 to 1848, the issue of slavery in the new territories led to the Compromise of 1850 . While the compromise averted an immediate political crisis, it did not permanently resolve the issue of the Slave Power (the power of slaveholders to control the national government on the slavery issue). Part of the Compromise of 1850 was the Fugitive Slave Law of 1850, which many Northerners found to be extremely offensive, and required that Northerners assist Southerners in reclaiming fugitive slaves . </P> <P> Amid the emergence of increasingly virulent and hostile sectional ideologies in national politics, the collapse of the old Second Party System in the 1850s hampered politicians' efforts to reach yet another compromise . The compromise that was reached (the 1854 Kansas--Nebraska Act) outraged many Northerners, and led to the formation of the Republican Party, the first major party that was almost entirely Northern - based . The industrializing North and agrarian Midwest became committed to the economic ethos of free - labor industrial capitalism . </P>

At the heart of the missouri compromise was the issue of