According to a 2017 review study of civil war research, there are three prominent explanations for civil war: greed-based explanations which center on individuals' desire to maximize their profits, grievance-based explanations which center on conflict as a response to socioeconomic or political injustice, and opportunity-based explanations which center on factors that make it easier to engage in violent mobilization.

For nearly a century, the people and politicians of the Northern and Southern states had been clashing over the issues that finally led to war: economic interests, cultural values, the power of the federal government to control the states, and, most importantly, slavery in American society.