On September 16, 1862, as a fog enveloped what would be the Antietam battlefield, Union “right wing” commander General Ambrose Burnside had a startling meeting with 9th corps commander Jacob Cox. Burnside told him that despite his 9th corps’ great success at the September 14 Battle of South Mountain, Union commander George McClellan had, the day before, “rewarded” Burnside by cutting his authority in half. Burnside’s other corps, the 1st, led by Joe Hooker, would now act directly under McClellan’s authority and be the right flank of the army. The 9th corps, McClellan decided, would now be the left flank of the army.
A miffed Burnside, complaining (with good reason) that he had been undercut by either the ever-conniving Hooker or 5th corps commander Fitz-John Porter, reacted petulantly to McClellan’s ill-timed and wrong-headed decision. Advising Cox that it would be beneath his dignity as a wing commander to lead only a corps, he devised a unique and inefficient approach to command authority. He told Cox that when he got orders from McClellan that he would read them and hand them to Cox to carry out. (As Cox would write to his wife a few days later, Burnside was now in effect commanding one man, him, and he was commanding the corps).
Cox, who had only met Burnside ten days before and who had been 9th corps commander for two days after Jesse Reno was killed at South Mountain, protested that he had only a small staff and only knew less than half the troops in the corps. Burnside said he would lend him staff and that the decision was final.
Cox had no choice but to accept this peculiar and inefficient arrangement, and he was conflicted about it. On the one hand, he wrote later, he “had no ground for complaint” because he was being given significant authority in a position of trust, and this was another feather in his cap and that of his Kanawha division. On the other hand, “the position of second in command is always an awkward and anomalous one, and such I felt it.”
Historian Scott Hartwig has written that this and other decisions by McClellan at this phase of the campaign undid the “unity of command” of the Army of the Potomac. Their effect on September 17, 1862 at the Battle of Antietam have been the subject of endless debate ever since. The next blog will add to that debate.
Below are pictures of Burnside and Cox