Question

In what two ways did emancipation of the slaves harm the Confederate war effort?

Freed slaves joined the Union army.
The Confederacy lost the support of Southern white civilians.
The Confederacy lost the labor force that supported its army.
Freed slaves took all the Confederate ammunition.
Without slaves, the Confederacy had no more reason to fight.

Answer 1

Freed slaves joined the Union army
The Confederacy lost the labor force that supported its army.

Lincoln had surmised this effect in his emancipation proclamation. It served to weaken the confederate army beside denying what he termed as a slave nation foreign aid.