In the years prior to the American Civil War, a separate sense of cultural, political and economic identity developed and took hold between the North and the South that helped lead to the conflict. Sectionalism, which refers to loyalty to a section of a nation rather than to the nation as a whole, contributed to a Southern identity based not only on a distinctively different way of life, but on a geographically shared mistrust and apprehension towards the Northern way of life represented by the federal government and the election of United States President Abraham Lincoln. By the time of the election, the South had already developed its own sense of regional nationalism, based on a slave-labor agrarian economic system, that felt threatened by the anti-slavery stance of the heavily-industrialized North.
The cultural, social and economic institutions of the North and South were highly differentiated. Hotly contested and widely divergent moral positions were taken with regard to slavery and western expansion. An absence of the mass-communication methods which are now prevalent also contributed to the North and South becoming more isolated in their disparate views and traditions. Local news and opinion traveled much faster than nationwide communications and by the time the Southern States seceded from the Union, the U.S. had virtually become two separate nations.
Because the Southern states felt that President Lincoln favored the industrialized North at the expense of the agrarian South, particularly with regard to the issue of slavery, his election was viewed by Southerners as a blow to their well-being and honor. The great majority of European immigrants were also settling in the North. These factors played a role in fostering a defensive-aggressive mindset that eventually led to the Southern states' decision to formally secede from the Union.