The number of slaves in the north was minimal if not already abolished in the states of the North. The border states not in rebellion were problematic. Lincoln may have been many things, but he wasn't stupid.
Abraham Lincoln's Emancipation Proclamation of January 1863 was a masterful propaganda tactic, but in truth, it proclaimed free only those slaves outside the control of the Federal government--that is, only those in areas still controlled by the Confederacy. The legal end to slavery in the nation came in December 1865 when the Thirteenth Amendment was ratified, it declared: "Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction."OK, the GOP wrote and passed that amendment.
Abe wasn’t the great man you make him out to be, IMO.
“I am not in favor of Negro citizenship.”—Abraham Lincoln
On April 24, 1863, Lincoln issued General Order No. 100, known as the Lieber Code, which reiterated the accepted conventions of international law that existed at the time and which prohibited the intentional targeting of civilians in wartime. Those who did so were considered to be war criminals and should be prosecuted as such.
But from the very beginning, the Lincoln administration ignored its own Code as its armies pillaged, plundered, raped, and burned their way through the Southern states. In 1862 the entire town of Randolph, Tennessee, was burned to the ground by General Sherman even though there were no enemy combatants there. In 1863 Sherman burned Jackson and Meridian, Mississippi to the ground, again after the Confederate army had left. In a letter to General Grant, Sherman boasted that “for five days, ten thousand of our men worked hard and with a will, in that work of destruction, with axes, sledges, crowbars, clawbars, and with fire, and I have no hesitation in pronouncing the work well done. Meridian . . . no longer exists.”
Ninety percent of the buildings in Atlanta were destroyed despite the fact that there were no Confederate soldiers there, either. After the bombardment of Atlanta, an act that was prohibited by international law, Sherman evicted the remaining 2000 residents just as winter was arriving.
http://www.lewrockwell.com/dilorenzo/dilorenzo32.html