The major event in U.S. history representing the culmination of anti-slavery efforts was the Civil War (1861-1865). This conflict emerged primarily over the issue of slavery and states' rights, highlighting the deep divisions in the nation. Abolitionists had been persistently advocating for the end of slavery, and their efforts, combined with growing sectional tensions, ultimately led to war. The Emancipation Proclamation issued by President Abraham Lincoln in 1863 declared freedom for all enslaved people in Confederate states, marking a pivotal turning point. Ultimately, the war culminated in the passage of the 13th Amendment in 1865, which abolished slavery in the United States.