The violence broke out after the losing side in a presidential election refused to accept their defeat.
No, we're not talking about the January 6th Capitol Riots, but the American Civil War. On a basic level, the Civil War was little more or less than 11 states violently seceding from the Union after the 1860 election because they opposed the victorious candidate, Republican nominee Abraham Lincoln. Correctly or otherwise, they feared that Lincoln was an abolitionist and opponent of white supremacy, both ideals that they held to be central to their Southern identity. Despite Lincoln's repeated reassurances that he only wished to limit the expansion of slavery and would otherwise leave it untouched, the newly-formed Confederate States of America waged bloody war to form their own country so they could keep slavery intact.
