The Bloodiest Day

150 years ago today, approximately 113,500 Americans marched onto the field of battle - and fought each other. The Battle of Antietam outside Sharpsburg, Maryland on September 17, 1862 pitted the Union's Army of the Potomac under Major General George B. McClelland against Confederate General Robert E. Lee's Army of Northern Virginia.

The battle was a tragedy of epic proportions. 22,717 of the men who took the field that day became casualties: 3,654 killed, 17,292 wounded, and 1,771 captured or missing in action. Those totals make it the bloodiest single-day battle in American history. To put it in perspective, the total casualties for the Americans who landed on Omaha Beach during D-Day were about 5,000 KIA, WIA, & MIA.


I've chose deliberately here to combine the casualty counts for the Union and Confederate forces. There was a "right" side and a "wrong" side to the American Civil War, but it was still Americans vs. Americans. Really, looking back on the carnage of a century and a half ago, I'm struck by the magnitude of how we were able to slaughter ourselves.

The battle at Antietam Creek could have been a turning point in the war. Militarily, it wasn't; politically, that's a different story. Lee had led his army north into Maryland to commandeer supplies, influence the 1862 election in a pro-peace direction, and hopefully gain favor amongst the local border state population. Maryland, indeed, was a slave state.

Lee's plans for battle had fallen into McClelland's hands. Amazingly, McClelland hesitated to act on Lee's own orders to his subordinates to bring the Army of the Potomac decisively to bear on Lee's dispersed army. Even during the battle, McClelland kept his headquarters well to the rear and wasn't able to directly influence the course of the battle, nor were his corps and division commanders aware of his "commander's intent" beyond their own sectors of the field. McClelland's hesitation also meant that Lee had time to learn that his plans had been lost; and to react accordingly.

The battle was a bloody standoff. The sides parried back and forth, attacking and counter-attacking. The failure of McClelland to concentrate the mass of his army was offset by Lee's (and corps commanders James Longstreet and Stonewall Jackson's) ability to maneuver and react to each thrust.

At the end of the day, Lee - with the Army of Northern Virginia's back to the Potomac River - was allowed to escape back into Virginia, though even after the horrific losses of the day, McClelland possessed a near 2:1 advantage over the Confederates.

Could a commander bolder and more decisive than McClelland have ended the war, or at a minimum hastened its end, that day by destroying Lee's army? We'll never know, but we do know that the Maryland Campaign was just Lee's first attempt at an invasion of the North. Not quite ten months later, the two opposing armies of Americans would show that the one-day horror of Antietam would be eclipsed by a three-day slaughter.

Antietam, with the Confederate Army beaten back out of Union territory albiet intact, gave President Lincoln the "victory" from which he needed to change the focus of the war by preliminary issue of the Emancipation Proclamation on September 22nd, to take effect 100 days later on January 1, 1863. Ironically, the battle fought in Maryland freed none of the slaves in that state, as the proclamation was limited to the areas in rebellion that weren't occupied by Union forces.

Finally, as a resident of the Pittsburgh area, I'd be remiss in pointing out that it's also the 150th anniversary of the disaster at the Allegheny Arsenal. The arsenal was making ordnance for the Union Army when three catastrophic explosions rocked the area killing 78 workers, most of them young women. It was the largest single civilian tragedy of the Civil War, and is understandably lost in the carnage that was Antietam.