On Jan. 1, 1863, Abraham Lincoln issued the Emancipation Proclamation. Analysis of that famous document often focuses on what was done for the slaves and why. It dissects whom the proclamation did and did not free as well as the legal and military justifications Lincoln gave for the action.

However, the proclamation also empowered African-Americans, whether born free or enslaved, to act in the cause of liberty. The proclamation declared “that such persons of suitable condition, will be received into the armed service of the United States to garrison forts, positions, stations, and other places, and to man vessels of all sorts in said service.” African-Americans could join the Union cause through military enlistment.

The most famous result of this new opportunity was the formation of the 54th Massachusetts, the Civil War’s most famous all-black regiment, and the subject of the 1989 film Glory. On instructions from Secretary of War Edwin Stanton, the state of Massachusetts began forming a regiment of only African-American enlisted men less than a month after Lincoln issued the proclamation. Two sons of Frederick Douglass signed up. The all-white officers included Robert Gould Shaw, the son of prominent Boston abolitionists whom the Massachusetts governor tapped to lead the regiment. Trained in Boston, they arrived in June of 1863 in South Carolina to join the forces of Major General David Hunter.

This week marks the 160th anniversary of that famous unit’s most heralded act: The assault on Fort Wagner. The fort comprised part of the defense system of Charleston, South Carolina. It was a formidable structure, well garrisoned and well positioned to repulse an attack. Leading the assault, the 54th was decimated by Confederate artillery and musket fire. The regiment suffered more than 40% casualties, including the death of Colonel Shaw.

The attack failed to capture the fort. Yet the battle proved a minor defeat. The bravery of the 54th Massachusetts inspired developments crucial to winning the war. First, it drove enlistments among African-Americans. In the end, 180,000 joined, a crucial, even decisive, infusion of manpower. Second, the fame of the 54th gained hard-won respect among northern whites for African-American soldiers. In a March 1863 letter to his father, Shaw wrote of the receding skepticism about African-Americans’ ability to make good soldiers. “The skeptics need only come out here now, to be converted,” he proudly declared. Fort Wagner did the work of conversion. General Grant, for instance, expressed hearty support for their recruitment and use in the war effort in the weeks following the Fort Wagner assault.

The story of the 54th Massachusetts is the story of fulfilling the promise made in the American founding. In our Declaration of Independence, we committed ourselves to the truth of human equality, even as our practice of slavery contradicted that commitment. The Emancipation Proclamation, out of which the 54th was formed, dedicated the war effort to aligning our practice with our principles. It ended all ambiguities about the Union cause, including equal liberty for all.

The 54th itself helped make that dedication a realization. It did so in its own bravery and the inspiration those deeds gave to others. Those men lived out the principle of equality off the battlefield as well, refusing to take reduced pay compared to white soldiers. And even how they died displayed the cause. Colonel Shaw was buried with his soldiers by the Confederates, done as an insult. But Shaw’s father, upon hearing the news, found it a point of honor for Shaw to be laid to rest with his men.

Let all Americans celebrate the heroism of the 54th Massachusetts. They did not die in vain. Their legacy joins that of the Emancipation Proclamation itself: A victory for human equality, for human liberty, and for the cause of justice.

Adam Carrington is an assistant professor of politics at Hillsdale College.