How did the Emancipation Proclamation impact the course of the Civil War?

The Emancipation Proclamation was a major turning point in the Civil War in that it changed the aim of the war from preserving the Union to being a fight for human freedom, shifted a huge labor force that could benefit the Union war effort from the South to the North and forestalled the potential recognition of the Confederacy by England or France.

Explanation:

a historian researching the immigration policies of the early 1900s would expect a source written today,rather than in 1910 to :

( a ) be more interested in objective data and statistics.