After the battle of Antietam, fought on September 17, 1862, Mathew Brady, Civil War photographer, premiered something novel in New York City. Before, there had only been names of the dead and wounded listed in the newspapers. But as of October 20, 1862, reported the New York Times, Brady had opened a new venue of horror. “At the door of his gallery hangs a little placard, ‘The Dead of Antietam.'” Crowds were fascinated and thronged the gallery. “You will see hushed, reverend groups standing around these weird copies of carnage, bending down to look in the pale faces of the dead, chained by the strange spell that dwells in dead men’s eyes.” (“Brady’s Photographs”, NYT, Oct. 20, 1862)
Antietam was the bloodiest single-day battle in American history. The advance of Confederate General Robert E. Lee and his soldiers into Maryland was halted there by Union General George McClellan and his men.
Allan Pinkerton, chief of the Union’s Secret Service at the time of Antietam, later wrote that the Federal troops were exhausted after the battle. “The serious losses sustained at South Mountain, Crampton’s Gap, and Antietam had left the army badly disorganized, and the privations and hardships to which they had been subjected, rendered a delay, for the purpose of allowing the worn and weary soldiers time to rest and recuperate, an absolute necessity.” (“The Spy of the Rebellion”, by Allan Pinkerton)
Yet notwithstanding the exhausted state of the Union army, the “political cabal” in Washington, DC wasted no time in complaining that General McClellan had not pursued his advantage and chased after General Lee and his retreating army. (Pinkerton, op. cit.)
It was the Union victory at Antietam which persuaded President Abraham Lincoln to publicly issue the Emancipation Proclamation, proclaiming all those enslaved in Confederate territory to be forever free. Gideon Welles, Secretary of the Navy under Lincoln, described the special Cabinet meeting of September 22, 1862 in his diary:
President Lincoln remarked 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 that it was his duty to move forward in the cause of emancipation. It might be thought strange, he said, that he had in this way submitted the disposal of matters when the way was not clear to his mind what he should do. God had decided this question in favor of the slaves.” After minor amendments added by Secretary of State William Seward, the Emancipation Proclamation “was then handed to the Secretary of State to publish to-morrow.”
But the Postmaster-General, Montgomery Blair, though approving the measure overall, worried that by issuing the Proclamation a club had been put in the hands of “a class of partisans in the Free States [who were] endeavoring to revive old parties…” Such Copperheads would avail themselves of the “club” (Emancipation Proclamation) handed to them and use it to “beat” the Lincoln Administration. (Diary of Gideon Welles)