<P> The Republican Party wanted to achieve the gradual extinction of slavery by market forces, because its members believed that free labor was superior to slave labor . Southern leaders said that the Republican policy of blocking the expansion of slavery into the West made them second - class citizens, and they also said it challenged their autonomy . With the 1860 presidential victory of Abraham Lincoln, seven Deep South states whose economy was based on cotton and slavery decided to secede and form a new nation . The American Civil War broke out in April 1861 with the firing on Fort Sumter in South Carolina . When Lincoln called for troops to suppress the rebellion, four more slave states seceded . </P> <P> Lincoln's Emancipation Proclamation was an executive order of the U.S. government issued on 1 January 1863, changing the legal status of 3 million slaves in designated areas of the Confederacy from "slave" to "free". Slaves were legally freed by the Proclamation and became actually free by escaping to federal lines, or by advances of federal troops . Many served the federal army as teamsters, cooks, laundresses, and laborers . Plantation owners, realizing the emancipation would destroy their economic system, sometimes moved their slaves as far as possible out of reach of the Union army . By "Juneteenth" (19 June 1865, in Texas), the Union Army controlled all of the Confederacy and liberated all its slaves . The owners were never compensated . </P> <P> The border states were exempt from the Emancipation Proclamation, but they too (except Delaware) began their own emancipation programmes . When the Union Army entered Confederate areas, thousands of slaves escaped to freedom behind Union Army lines, and in 1863 many men started serving as the United States Colored Troops . The 13th Amendment to the U.S. Constitution took effect in December 1865 and finally ended slavery throughout the United States . It also abolished slavery among the Indian tribes, including the Alaska tribes that became part of the U.S. in 1867 . </P> <P> White and Black opponents of slavery, who played a considerable role in the movement . This list includes some escaped slaves, who were traditionally called abolitionists . </P>

In the 1830s congress felt the most pressure over abolition from