September 17, 1862: High Tide of the Confederacy?

Mackubin T. Owens

September 1, 2004

Friday, September 17th is the 142nd anniversary of the 1862 battle that still stands as the bloodiest day in American history: nearly 6,000 Americans were killed and another 19,000 were wounded or went missing near Sharpsburg, Maryland. Controversy has surrounded the battle from the start. On the one hand, the majority opinion holds that Confederate General Robert E. Lee exhibited outstanding tactical leadership during the battle. Time after time, Lee, with his back to the Potomac and badly outnumbered, was able to avert disaster by shifting his forces from one part of the field to another. That the battle ended as a tactical draw is seen as a tribute to Lee’s generalship.

He was able to accomplish what he did because he exploited the over-cautiousness of his opponent, George McClellan. Indeed, in the words of one historian, “it was almost as if Lee was pulling the strings of a Federal puppet.” So well did Lee understand McClellan that he could risk facing the Army of the Potomac with his back against the Potomac, then remain on the field another day after losing a quarter of his already outnumbered force, despite the fact that McClellan had at his disposal reserves that had not been committed on the 17th.

On the other hand, a small but vociferous band of Lee’s critics, including J.F.C. Fuller, Thomas Connelly, and Alan Nolan, have portrayed Lee’s decision to stand at Antietam as just one more example of a single-minded offensive orientation that led to casualties the Southern Confederacy could not afford. According to his detractors, Lee had no grand strategy and therefore focused narrowly on defeating the adversary at hand, no matter the cost in casualties. Lee’s predilection for the offensive not only hastened the defeat of the South but also was a major contributing cause of that defeat. In the words of Mr. Connelly, the Confederacy would “have fared better had it not possessed” a leader as aggressive as Robert E. Lee.

But even some of Lee’s warmest defenders have questioned his decision to offer battle under such disadvantageous circumstances. E. Porter Alexander, Lee’s ordnance chief and one of the most perceptive contemporary observers of Lee and his Army of Northern Virginia, called his decision to stand at Antietam “the greatest military blunder that Gen. Lee ever made.”

If the battle of Antietam remains controversial, profound disagreement also attends the entire campaign that culminated in the battle. What was Lee’s objective when he entered Maryland in September of 1862? Was his incursion a spontaneous and isolated movement or was it consonant with a conscious and comprehensive Confederate strategy?

Regarding the first question, most historians have seen the Maryland campaign as a full-scale invasion of the North intended to reach the banks of the Susquehanna. Its goals included relieving Virginia from the scourge of foraging armies by subsisting for as long as possible off enemy resources; enticing Maryland into secession; strengthening the Northern peace party in the upcoming congressional elections; and encouraging recognition by Great Britain and France. Others have demurred, claiming the entire campaign was always intended to be a raid.

Regarding the second question, many historians have interpreted the Maryland campaign as an isolated maneuver, another manifestation of Lee’s innate aggressiveness as a commander. Some have gone so far as to suggest that Lee’s forays into Union territory were undertaken primarily to maintain his claim on scarce Confederate resources that might have been used to greater strategic purpose in the West.

My understanding of Lee’s foray into Maryland has been greatly influenced by Joseph L. Harsh’s Taken at the Flood: Robert E. Lee and Confederate Strategy During the Maryland Campaign of 1862. Mr. Harsh’s signal contribution to our understanding of this campaign, and by extension to the war as a whole, is to transcend issues of personality—”Robert the Bold vs. George the Timid”—in order to focus on strategic considerations.

Taken at the Flood is a serious and detailed examination of Lee’s strategic, operational, and tactical decisions in the context necessary to understand those decisions—in other words, an attempt to see the campaign through Lee’s eyes. Critical of history as twenty-twenty hindsight, Mr. Harsh takes pains to establish, insofar as possible, the precise locations, routes, times, weather conditions, and other factors that influenced Lee’s strategic decision and their execution during the Maryland campaign. Recognizing the importance of perceptions in the face of what Carl von Clausewitz called the “fog of uncertainty” in war, Mr. Harsh tries to establish what the Confederate commander knew at the time rather than what we know now.

Mr. Harsh rejects the argument that Lee’s decision to enter Maryland was a spontaneous and isolated military movement taken without the approval of his government. He persuasively demonstrates that it was part of a comprehensive Confederate strategy designed to achieve independence. Additionally, he shows that this strategy was not the defensive one traditionally attributed to the Confederacy.

To understand fully Lee’s decision to enter Maryland in September 1862, it is necessary to examine Confederate war aims, policy, and strategy from the beginning of the war. Mr. Harsh did this in the companion volume to Taken at the Flood published in 1998, Confederate Tide Rising: Robert E. Lee and the Making of Southern Strategy, 1861-1862. Here he argued that “the Confederacy pursued three closely related but distinct war aims: independence, territorial integrity, and the union of all the slave states.” To achieve these interrelated goals required “to a greater or lesser degree, aggressive military operations.”

The key to Confederate strategy, as understood by both President Jefferson Davis and Lee, was the recognition that as long as the North remained determined to subdue the South, the Confederacy could not win its independence. The Northern population had to be demoralized in order to force the Union to abandon the war. A defensive strategy would not work because the Confederacy lacked the necessary strategic depth and because reliance on the defensive played to Northern strengths in engineering, artillery, and the navy, minimizing Union losses and allowing the North to succeed with far less than full mobilization.

Lee aimed to change the character of the war as things stood in the spring of 1862, employing the strategic turning movement and open-field maneuvering by infantry and cavalry to neutralize the Union’s advantage in engineering, artillery, and gunboats. For Lee, maneuver was not an end in itself but the means to gain an advantage in order to attack the enemy and inflict heavy losses. Only in this manner, Lee believed, could the population of the North be convinced that a costly and interminable struggle lay ahead if the South were not granted its independence.

Thus the Maryland incursion can be seen as the third phase of a unified campaign that began on the banks of the Chickahominy on June 26. In a series of turning movements during the Seven Days campaign, Lee drove McClellan back from Richmond. Although Union forces prevailed in most of the tactical engagements during this operation, the strategic result was that Richmond was spared the siege that inevitably would have led to it fall.

Once Lee had pushed McClellan back to the James, Lee detached Stonewall Jackson to confront John Pope’s Army of Virginia to the north. Even before he was certain that McClellan was withdrawing from the Peninsula, Lee dispatched James Longstreet to gain Pope’s rear, then unleashed his entire army in a furious assault against Pope at Second Manassas. Although Pope escaped destruction, the operation ended in a Federal rout that demoralized the Federal government and the army and placed Lee as close to Washington as McClellan had been to Richmond only two months earlier.

Lee now contemplated an incursion into Maryland, not to invade the North or to conduct a raid, but as the logical follow-up to the smashing victory at Second Manassas. He intended to inflict another humiliating defeat on the demoralized Union forces, this time in western Maryland.

The time was ripe. Not only had Lee’s efforts up to now been crowned with success, but also Lee knew that with the April Conscription Act, the Confederacy had exerted its maximum effort to bring troops into the field while, the North had barely tapped its manpower reservoir. Meanwhile, the Confederate armies in the West were on the move toward the Ohio. The Confederacy was indeed at flood tide. In the absence of success, the tide would only recede.

Mr. Harsh writes that “the single tapestry” of the campaign “[stretching] from Beaver Dam Creek on June 26 to Shepherdstown on September 20… represented a calculated attempt to restore Confederate resources, to demoralize the North, and to win the war in the summer of 1862.” Lee believed that “the Confederacy had reached the fulcrum of its fate” and judged that “it was necessary to risk all because a similar opportunity most likely would never come again.” Mr. Harsh believes Lee’s strategic perception to be correct. “Lee’s strategy to demoralize the North, and for the most part his execution of that strategy gave the Confederacy the best chance it would ever have to win its independence.”

While Mr. Harsh redeems Lee the strategist, he reveals flaws in Lee the practitioner of operational art. The Maryland campaign began to unravel because of two fundamental operational errors on Lee’s part. First he underestimated his opponent. Second, he attempted too much with the limited resources available to him.

Lee first underestimated the time it would take to deal with the Federal garrisons at Martinsburg and Harper’s Ferry. Their failure to respond as Lee expected disrupted his timetable and put at risk his divided force. But more importantly, Lee underestimated the rate and character of the main Federal advance toward western Maryland. The conventional wisdom has usually attributed the rapidity of this advance to the “Lost Dispatch,” a copy of Lee’s Special Order 191 that fell into Union hands. According to this view, McClellan now knew Lee’s plan and the disposition of his divided army.

But Mr. Harsh discounts the claim that S.O. 191 was decisive. He points out that McClellan was already moving “more rapidly than convenient” against Lee’s rear before the discovery of the order. Lee was largely unaware of McClellan’s progress because of the failure of Stuart’s cavalry to provide the necessary intelligence—he was genuinely surprised when McClellan reached Frederick on September 12. Additionally, S. O. 191 gave McClellan no information about the strength of Lee’s army or its constituent parts.

To implement a strategy, it is necessary to have the right tactical instrument. “On September 2,” writes Mr. Harsh, “Lee’s army was an instrument of sufficient strength and mettle to justify crossing the Potomac. From the 14th onward, however, his unrelenting demands blunted the weapon in his hands and reduced its power.” Though not as small as the mythology of the Lost Cause would have it, the Army of Northern Virginia was still at a disadvantage in the event of a stand-up fight. By the time Lee had lost his last opportunity to gain an advantage by maneuver, his capacity either to do so or stand and fight was severely limited. His soldiers had been scattered across western Maryland from Hagerstown to Pleasant Valley by the heat, the forced marches, and the confusion of retreats. Lee had asked too much of his soldiers.

However, as late as the early afternoon of September 16, Lee fully intended to renew his offensive by drawing McClellan to the west where he could gain an advantage by maneuver. He had paused at Sharpsburg not to fight but to permit his army to reunite after the surrender of Harper’s Ferry. Only after Stuart reported that McClellan’s troops were crossing the upper Antietam did he grudgingly accept a defensive battle, his maneuver option now foreclosed.

Mr. Harsh portrays Lee’s actions during the battle and after not bold so much as desperate. He took the steps he did to salvage the strategy he believed offered the best chance for Confederate victory. And he failed. In the words of James Longstreet, “At Sharpsburg was sprung the keystone of the arch upon which the Confederate cause rested.”

Reflecting the judgment of Longstreet, Mr. Harsh contends that Antietam, not Gettysburg marked the high tide of the Confederacy. “The tide ran too shallow and the shore stretched too far.” Lee would win other victories and indeed, would invade the North again. But this time instead of operating in conjunction with Confederate armies in the West, he would be trying to offset reverses at Vicksburg and Chattanooga. Also by then, the material disparities between the Union and the Confederacy, exacerbated by emancipation, had begun to tell.

Mackubin Thomas Owens is an Adjunct Fellow of the Ashbrook Center and a professor of strategy and force planning at the Naval War College in Newport, R.I. He led a Marine infantry platoon in Vietnam in 1968-1969.