The Emancipation Proclamation
Five days after the Battle of Antietam, President Abraham Lincoln summoned his cabinet to the White House. He reminded them of the proclamation draft he had read to them in July and said he had resolved that if Robert E. Lee was driven out of Maryland, he would issue the proclamation. Lincoln said, “I think the time has come now. I wish that we were in a better condition. But the rebel army is now driven out, and I am going to fulfill that promise.” 
Thus, Lincoln issued the preliminary draft of the Emancipation Proclamation, declaring “that all persons held as slaves” within rebellious areas “are, and henceforward shall be free” if those areas did not return to the Union within 100 days, or January 1. The decree was made public on September 24.
The proclamation technically freed no one because it only freed slaves in seceded states, which considered themselves part of a separate nation and not bound by Federal authority. Slave states remaining loyal to the Union (Maryland, Delaware, Kentucky, and Missouri) were exempted, as were southern regions under Federal military occupation, mostly in Louisiana. Seceded states would also be exempted if they renounced secession and returned to the Union by January 1.
Lincoln cited “military necessity” under his power as commander-in-chief to issue such a proclamation. However, outraged southerners viewed this as an unconstitutional attempt to make law, which was a right belonging only to Congress. Southerners also believed this was an attempt to encourage slaves to rebel against their masters, which was especially despicable since most masters were off to war, leaving women and children to fend for themselves against potentially hostile slaves. However, the proclamation ultimately caused no mass slave uprisings.
Knowing that the proclamation was unconstitutional and could not be enforced without military success, Lincoln hoped to achieve two goals. First, he sought to turn European opinion against the South by making the war a moral struggle between a slaveholding nation and a nation taking the first steps toward ending slavery. Second, Lincoln sought to motivate slaves to escape their masters and support the Federal cause.
The Emancipation Proclamation radically shifted the primary Federal war aim from preserving the Union to freeing slaves. This drastically changed the scope of the war and subsequent American history. While it had no constitutional authority, it ultimately paved the way for a constitutional amendment permanently abolishing slavery in America.
