Why did it take so long for the union to finally accept African Americans into to the army?

The delay in the Union's acceptance of African Americans into the army during the Civil War was primarily due to prevailing racial prejudices and the belief that Black soldiers would be less capable or reliable than their white counterparts. Initially, military leaders feared that enlisting African Americans would lower the morale of white troops and complicate the war effort. However, as the war progressed and the need for manpower increased, along with evidence of African Americans' bravery and effectiveness in battle, attitudes shifted, leading to their eventual enlistment in significant numbers. By the war's end, approximately 180,000 African Americans had served in the Union Army, proving their valor and commitment to the fight for freedom.