In the summer of 1862, President Abraham Lincoln, long urged by abolitionists to free the slaves, discussed a preliminary Emancipation Proclamation with members of his Cabinet, including Secretary of State William Seward and Navy Secretary Gideon Welles. All agreed that the order should be tabled until after a major Union victory.
For Lincoln, that victory was the Battle of Antietam in September. Five days after the battle, Lincoln read the Emancipation Proclamation to his entire Cabinet, making it an effective law as of January 1, 1863. Lincoln justified issuing the order under his powers as Commander-in-Chief of the armed forces.
The Emancipation Proclamation Critics
As it was first issued, the Emancipation Proclamation freed all the slaves in territories still in rebellion. Critics charged that the law did not actually free a single individual. However, between 20,000 and 50,000 slaves were immediately freed, with more slaves receiving their freedom with the advance of the Union armies. Slaves who escaped to Union lines were freed, and allowed for freed men to enroll in the Union Army.
The Emancipation Proclamation was, however, a first step towards the abolition of slavery in the United States, a process completed with Union victory in the Civil War and passage of the 13th Amendment, which went into effect on December 18, 1865. It transformed the Civil War into a struggle over slavery and the meaning of freedom.