Final answer:
During the Civil War, the Union initially returned escaped slaves and refused to enlist even free blacks. However, as the war progressed, over 190,000 African Americans enlisted as soldiers.
Step-by-step explanation:
During the American Civil War, the Union government initially returned escaped slaves to their masters instead of enlisting them in the army. However, as the war progressed, the Union began to allow African Americans to serve as soldiers, resulting in over 190,000 enlisting by the end of the war. The Union Congress was concerned about the reaction of the Border States to black troops, and racism among white soldiers fueled the belief that black soldiers could not be effective or trustworthy, limiting their roles to labor tasks like hauling supplies and digging trenches.