Answer:
President Abraham Lincoln delivered his famous Emancipation Proclamation in 1863, in the midst of the Civil War against the southern states, united in the Confederacy. In it, African American slaves who were in the south of the nation, that is, in the Confederation, were freed. Through this strategy, Lincoln sought to foment slave rebellions, as well as win the favor of African Americans and, ultimately, deprive Southerners of the enormous labor that they provided.
However, President Lincoln did not do the same with the slaves in the north, mainly due to two factors: on the one hand, there were far fewer slaves and slavery was abolished in a large number of northern states, and on the other, to maintain this manpower until the end of the war.