The Princeton historian James McPherson, reviewing a number of new books on Lincoln, deconstructs criticisms of the Emancipation Proclamation, focusing particularly the claim "that Lincoln 'freed' the slaves in areas where he had no power, and left them in slavery where he did have power":
Nothing could be more wrong. For one thing, tens of thousands of ex-slaves lived in parts of the Confederacy that were occupied by Union forces but were not exempted from the proclamation. They celebrated it as their charter of freedom. For that matter, so did many slaves in exempted areas, which included the four slave-holding states that never left the Union (Missouri, Kentucky, Delaware, and Maryland) as well as Confederate areas that had been returned to Union control, such as New Orleans and the forty-eight Virginia counties that would soon become West Virginia. They recognized that if emancipation took hold in the Confederate states, slavery could scarcely survive in the upper South.
The proclamation officially turned the Union army into an army of liberation—if it could win the war.
And by authorizing the enlistment of freed slaves in the army, the final proclamation went a long step toward creating that army of liberation. If the Emancipation Proclamation was merely a piece of paper that did not actually free anyone, as skeptics then and later charged, the Declaration of Independence was likewise a mere piece of paper that did not in itself create a new nation. Both outcomes depended on victory in a war to which these documents gave new purpose.
Previous Dish on Lincoln and the Emancipation Proclamation here.
(Image: "Emancipation from Freedmen's Viewpoint," an illustration from Harper's Weekly circa 1865, from Wikimedia Commons)