90 ARMY September 2012 Photographs by Dennis Steele
Antietam at 150 By BG John S. Brown U.S. Army retired September 17 marks the 150th anniversary of the Battle of Antietam, the bloodiest single day in American history. The battlefield, not far from Washington, D.C., still retains much of its original character. The campaign remains a case study in operational maneuver and the battle a testimony to courage under fire. September 2012 ARMY 91
The Lower Bridge spans Antietam Creek on Antietam National Battlefield, Md. Today it is referred to as Burnside s Bridge for MG Ambrose E. Burnside, whose corps finally advanced across it after being blocked by about 500 Confederates for three hours during the Battle of Antietam. Two major attacks were repulsed, but the Federals succeeded with a third attack. In the July issue we discussed Union GEN George B. Mc- Clellan s Peninsular Campaign and its inglorious end. Learning that McClellan was withdrawing his army by sea from the peninsula, Confederate GEN Robert E. Lee broke away and hastened to defeat Union forces in northern Virginia before McClellan could rejoin them. These were commanded by MG John Pope, a capable general but no match for Lee and his brilliant principal subordinates, BG John S. Brown, USA Ret., was chief of military history at the U.S. Army Center of Military History from December 1998 to October 2005. He commanded the 2nd Battalion, 66th Armor, in Iraq and Kuwait during the Gulf War and returned to Kuwait as commander of the 2nd Brigade, 1st Cavalry Division, in 1995. He has a doctorate in history from Indiana University. His book, Kevlar Legions: The Transformation of the U.S. Army, 1989 2005, was published in 2011. Thomas J. (Stonewall) Jackson and James Longstreet. In a series of masterful maneuvers, the Confederate generals turned Pope s flank, forced him into a battle to recover his lines of communications and handed him a stinging defeat at the Second Battle of Bull Run (Second Manassas). Union forces fell back on Washington, D.C., where they were absorbed into a larger whole that included McClellan s returning Peninsular veterans. Pope was exiled to St. Paul, Minn., there to take command of the Northwest Department. McClellan assumed command of the combined forces and did a commendable job of reorganizing, retraining and reinvigorating them. McClellan was at his best when not on the field of battle. President Abraham Lincoln had appointed Henry W. Halleck as his General in Chief in July 1862, but Halleck assumed a role as military advisor to the President rather than attempt the direct exercise of field or strategic command. 92 ARMY September 2012
A current view of Dunker Church shows the National Park Service sign with a photograph of casualties on the same ground. The church was the objective for attacks on the morning of the battle by Union corps under MG Joseph Hooker and MG Joseph K.F. Mansfield. The memorial to the Union s Irish Brigade honors soldiers who fell in the battle of Bloody Lane. As capable as McClellan s reconstruction of the Army of the Potomac was, Union mobilization practices embodied a flaw that would continue to haunt commanders on the battlefield. Rather than placing a priority on bringing veteran regiments back up to full strength after combat losses, the Union favored raising entirely new units. Among the perceived advantages, this practice reduced the burdens of administering existing units at a distance and offered additional command positions with consequent opportunities for patronage. During this period only 50,000 recruits replaced combat losses, whereas 420,000 went into totally new units. As a result, regiments with combat experience withered, and regiments without combat experience continued to be thrown into battle underprepared. Lee knew he could not rest on his laurels after Second Bull Run, nor was he inclined to. On September 4 he invaded Maryland, both to retain the initiative and in the hope that Marylanders could be induced to join the Confederacy. Maryland was a slave-holding state, and sentiment for the South there was strong. The invasion offered opportunities to sever vital Union east-west rail communications, seize the critical depot of Harpers Ferry, W. Va., move the fighting away from Virginia, and operate against such major northern cities as Baltimore, Philadelphia, and Washington, D.C. Lee s aspirations were Union nightmares. McClellan alleged he did not despair of saving the capital but nevertheless considered it prudent to ship the family silver elsewhere. On September 13 McClellan was handed a copy of Lee s Special Order No. 191. One of his soldiers had found it in an abandoned Confederate campsite and recognized its importance. This intelligence coup revealed that the Confederates would be strung out from Harpers Ferry where Jackson was besieging a garrison of 12,000 to Hagerstown, Md., and beyond. Little blocked McClellan s approach from Washington through Fredericksburg, Va., to cut across this line of communications. McClellan acted on this intelligence windfall, but the next day rather than immediately. Lee, meanwhile, recognizing that critical intelligence had been compromised, speedily threw blocking forces into Turner s Gap and Crampton s Gap in Maryland while withdrawing the rest of his army in the direction of Sharpsburg on the Potomac River. Enterprising Union corps commanders forced both gaps, but they lost a day doing it. McClellan proceeded cautiously, convinced he was outnumbered even though he had an overall numerical advantage of 84,000 to 55,000. Harpers Ferry, surrounded and bombarded on all sides from neighboring heights, surrendered during the morning of September 15. This freed Jackson s considerable besieging force to rejoin Lee. Lee took up a position at Sharpsburg facing east across Antietam Creek. Vegetation and irregularities in the ground offered cover, but his back was against the Potomac River, and the higher ground was on the Union side of Antietam Creek. McClellan s forces arrived on the afternoon of September 15. McClellan consumed the next day with skirmishing, reconnaissance and the formulation of plans. Jackson s force, meanwhile, marched from Harpers Ferry and assumed responsibility for the sector that would become the axis of the Union s main attack. Early on September 17 two Union corps, commanded by MG Joseph Hooker and MG Joseph K. F. Mansfield, smashed into the Confederate left flank. They forced their way forward in heavy fighting but were checked by savage counterattacks and enfilading artillery fire. Mansfield was killed and Hooker wounded. Subordinate commanders tried to regain the momentum of the attack but became disorganized. The divisions of MG Edwin V. Sumner s II Corps marched in to reinforce the attack but became separated and misdirected during their approach. They deployed piecemeal in different places. The first to arrive was so badly mauled it was almost immediately combat-ineffective. The remaining two divi- September 2012 ARMY 93
Above, a memorial overlooking Dunker Church honors Maryland soldiers who fought in the Battle of Antietam. Inset left, a bronze memorial of stacked rifles supporting a cooking pot honors the 90th Pennsylvania Regiment at Antietam. sions became embroiled in savage fighting for a sunken road labeled Bloody Lane ever since. Repeated Union attacks eventually forced the Confederates out of Bloody Lane. Confederate forces deployed north of Sharpsburg were now on their last legs, and a fresh Union corps was arriving. At this point McClellan, appalled by his losses and magnifying Confederate strength in his own mind, demurred from further attacks on this axis. McClellan s hopes for victory shifted to the Confederate right flank, against which MG Ambrose E. Burnside was to launch massive attacks. Twice Union columns were bloodily repulsed in assaults across the span thenceforward called Burnside s Bridge. On the third attempt they made it across. At about the same time, other Union columns crossed Antietam Creek at fords located nearby. By 3:00 p.m. Burnside was across the creek, and by 4:00 p.m. he was on the high ground east and south of Sharpsburg. Around this time Confederate MG A.P. Hill arrived on the battlefield with the last of the Confederate divisions from Harpers Ferry. Literally panting from their forced march, these unexpected reinforcements crashed into the Union flank and forced it back to Antietam Creek. Both sides had had enough. Lee held his positions throughout the day of September 18, and McClellan declined to attack them. Securing this moral victory, Lee skillfully withdrew across the Potomac that night. Outnumbered by almost two-to-one on the battlefield, Lee had fought to a draw, losing about 10,300 to approximately 12,400 on the Union side. To this butcher s bill, one might add the capture of Harpers Ferry and its garrison. Union troops had fought well, as had most of their commanders. McClellan himself had been cautious and indecisive, committing his forces piecemeal. Lee had been able to shift forces sufficiently to contain each attack in turn. Lee withdrew undefeated and was virtually untouched by pursuit. President Lincoln was, however, able to portray the indecisive carnage as enough of a victory to justify unveiling his Emancipation Proclamation. For the Union cause, this was a victory of a very different sort. Recommended Reading: Esposito, Vincent J., The West Point Atlas of American Wars, Volume I: 1689 1900 (New York: Frederick A. Praeger, 1959) Foote, Shelby, The Civil War, A Narrative, Vol. 1: Fort Sumter to Perryville (New York: Random House, 1958) Luvaas, Jay and Harold W. Nelson, eds., Guide to the Battle of Antietam (Lawrence, Kan.: University Press of Kansas, 1996) McPherson, James M., Battle Cry of Freedom: The Civil War Era (New York: Oxford University Press, 1988) Sears, Stephen W., Landscape Turned Red: The Battle of Antietam (Norwalk, Conn.: Easton Press, 1988) September 2012 ARMY 95