todaysdocument:

War Department General Order 143: Ordering the Creation of the U.S. Colored Troops, May 22, 1863

The outbreak of the Civil War set off a rush by free black men to enlist in U.S. military units. They were turned away, however, because a Federal law dating from 1792 barred Negroes from bearing arms for the U.S. Army. The Lincoln administration wrestled with the idea of authorizing the recruitment of black troops, concerned that such a move would prompt the border states to secede.  

However, following the Emancipation Proclamation and faced with dwindling white volunteers, black recruitment was pursued in earnest. Volunteers from South Carolina, Tennessee, and Massachusetts filled the first authorized black regiments. Recruitment was slow until black leaders such as Frederick Douglass encouraged black men to become soldiers to ensure eventual full citizenship. (Two of Douglass’s own sons contributed to the war effort.) Volunteers began to respond, and in May 1863 the Government established the Bureau of Colored Troops to manage the burgeoning numbers of black soldiers. By the end of the Civil War, roughly 179,000 black men (10 percent of the Union Army) served as soldiers in the U.S. Army, and another 19,000 served in the Navy.

via Our Documents