This may sound ridiculous, but many people actually believed that black men couldn't fight. African-Americans had fought in the Revolutionary War and the War of 1812. Of course they wanted to fight in this war. But neither side would have them. Frederick Douglass was furious about it. He said: "What upon earth is the matter with the American people? The national edifice is on fire. Every man who can carry a bucket of water is wanted. Yet our leaders refuse to receive the very class of men which has a deeper interest in the defeat of the Rebels than all others."

In the South, some slaves helped with the war effort; they farmed and worked in factories while white men were soldiers. Some slaves ran away to Yankee army camps. But what the African-Americans wanted to do was to fight. They wanted to fight because they knew—long before most white people—that this was a war about slavery. Finally it became possible. A month after Lincoln signed the final Emancipation Proclamation, a group of blacks fought as soldiers in Missouri. Soon there were legions of black soldiers . Assistant secretary of war Charles Dana visited General Ulysses S. Grant's army. He later said: "The bravery of the blacks completely revolutionized the sentiment of the army. I heard prominent officers who had sneered at the idea of Negroes fighting express themselves after that heartily in favor of it."

Before the war was over, 180,000 black soldiers would fight with the Union, and another 10,000 serve in the U.S. Navy. Massachusetts organized a regiment of black soldiers under the command of a young white Bostonian, Colonel Robert Gould Shaw. The men of the 54th Massachusetts led a bayonet attack on Fort Wagner —a massive fort of wood and earth that stood on an island at the entry to Charleston Harbor. Almost half were wounded, captured, or killed. After that no one asked if blacks could fight .