The secession of the Southern states was the culmination of a long conflict over enslavement that began even before the founding of the United States. When Europeans colonized the Americas, they began importing enslaved people from Africa, mainly for agricultural labor. These people were forced to work on labor-intensive cash crops like sugar, cotton, and tobacco. In the southern United States, cotton was especially profitable and became a major part of the South’s economy. The more rural, agricultural South depended on enslavement far more than the more urbanized and industrial North. As enslavement developed as an economic system in what would become the United States, race-based enslavement and discriminatory treatment of all people of African descent were encoded into law, starting with the 1662 Slave Code in Virginia and the 1685 Code Noir in French Louisiana. At the same time, racist ideas about African-Americans were increasingly solidified through 18th-century pseudo-science and invoked to justify the continuation of enslavement.

With the American Revolution and the establishment of the United States, the writers of the US Constitution were forced to incorporate the interests of the slaveholding planter class who tended to dominate politics in the South. This resulted in the Three-Fifths Compromise, which allowed slaveholding states to count their enslaved people as three-fifths of a person for the purposes of political representation.