What was the main issue that led to the Civil War in 1861?

The main issue that led to the Civil War in 1861 was the debate over slavery and states' rights. This conflict centered on the moral, economic, and political disagreements regarding the institution of slavery, particularly its expansion into new territories and states.

As the United States expanded westward, the question arose whether new states admitted to the Union would be free or slave states. This tension was exacerbated by the principle of states' rights, which held that states should have the authority to govern themselves and make decisions about issues like slavery without federal interference. Southern states championed this concept to defend their right to maintain and expand the institution of slavery, which they viewed as vital to their economy and way of life.

The culmination of these tensions led to a series of events, including the Missouri Compromise, the Compromise of 1850, and ultimately, the election of Abraham Lincoln in 1860, which prompted southern states to secede from the Union, sparking the Civil War. The deep-seated disagreements over slavery and whether states could exercise power in opposition to federal law encapsulated the central conflict that ignited the war.