High Stakes at Antietam


McClellan’s casualties on September 17 exceeded Lee’s, 12,400 to 10,300, and over the course of the Maryland campaign he lost 27,000 (including the Harpers Ferry captives) against Lee’s 14,000. In the weeks following Antietam the Young Napoleon’s continued posturing and maddening delays finally led the president to dismiss him.

The battle had other consequences. The fact that the Confederates were back in Virginia rather than in Maryland or Pennsylvania helped the Lincoln administration in the fall elections; despite electoral losses, the Republicans kept control of Congress. Of greatest importance, on September 22 Lincoln called his cabinet together to announce he was issuing the preliminary Emancipation Proclamation. He had been awaiting a battlefield victory to make it public; otherwise it might seem an act of desperation in a losing cause.

“The action of the army against the rebels has not been quite what I should have best liked,” the President told the cabinet, but the danger of invasion was over. He said he “had made a vow, a covenant, that if God gave us the victory in the approaching battle, he would consider it an indication of Divine will” and would move forward on emancipation. “God had decided this question in favor of the slaves.” On January 1, 1863, the slaves in any state in rebellion, he declared, “shall be then, and thenceforward, and forever free.”

Antietam and the resultant emancipation also ensured that the South would fight the war without friendly foreign intervention. The British and French had been leaning toward a role in the war—mediation, recognition of the Confederacy, perhaps military assistance—and setting considerable store by Lee’s string of victories. When it became a war to free the slaves as well as to restore the Union, no country would dare enter on the side of a slavery regime.

Antietam, in short, changed the course of the Civil War.