A major political event that occurred in the United States in 1861 was the outbreak of the Civil War. After years of rising tensions over issues such as states' rights, slavery, and economic differences between the North and South, the conflict began in April 1861 when Confederate forces attacked Fort Sumter in South Carolina. This led to a full-scale war between the Union (the North) and the Confederacy (the South), shaping the future of the United States. The war would ultimately determine the fate of slavery and preserve the Union, resulting in profound social, political, and economic changes across the nation.