African Americans’ service in US Armed Forces parallels their long struggle for liberation, citizenship, and equality. Notwithstanding the nation's purpose for war, they served in the past and today to help defend and make it more inclusive.

Blacks mustered during slavery. Colonial militias used many enslaved and free blacks in Indian wars, allowing some slaves to earn freedom. But growing fear of slaves’ rebellion led to black exclusion. Facing manpower needs in the Revolutionary War, the army enlisted slave and free black men from the North. They were mainly laborers, but about 5,000 bore arms. Thousands of bondmen escaped to the British side, there mainly laboring too; perhaps 1,000 engaged in fighting. Both sides promised liberty with land and/or a pension.

The color line endured in America. Northern states had begun gradual emancipation as Congress, in 1792, limited the army to “able-bodied white male citizens between the ages of 18 and 45.” In 1798 it excluded “Negroes, mulattos, and Indians” from the marines. Still, while conserving white privilege, the army and navy impressed black quotas in the War of 1812 (1812–15). By 1820 the army banned further black impressment and the navy adopted a 5 percent quota in 1839. Blacks thus were less visible in the Mexican-American War (1846–48) and ordinarily did routine labor. Southern militia companies, now all-white, assisted slave catchers.

Black military participation surged in the Civil War and increased afterward. Slaves fled to Union lines in droves and commanders started keeping them. Called “contraband of war,” they became paid workers and scouts before 1863, when the Emancipation Proclamation emancipated slaves of rebel masters and permitted blacks to join the army. Black enrollments, including women, approximated 200,000. Abolitionist Sojourner Truth was a nurse in a field hospital; Harriet Tubman a scout. Each also crusaded for justice during Reconstruction, when the army retained four black units: the 24th and 25th Infantries, 9th and 10th Cavalry Regiments. Whether “Buffalo Soldiers” in Indian Wars or “Smoked Yankees” in the Spanish-American and Philippine wars, they exhibited courage and dignity.

The War Department sustained the “invariable rule” of segregating African Americans. It deployed approximately 750,000 blacks within Jim Crow ranks during World War I, 90 percent of them in labor battalions.