Walt Whitman recalled the mood of the country in the summer of 1861, observing,
Nine-tenths of the people of the free States look’d upon the rebellion, as started in South Carolina, from a feeling one-half of contempt, and the other half composed of anger and incredulity. It was not thought it would be join’d in by Virginia, North Carolina, or Georgia. A great and cautious national official predicted that it would blow over ‘in sixty days,’ and folks generally believ’d the prediction.’
Events proved otherwise. The expected ease of victory against the Confederate foe was confounded by Confederate victory at the Battle of 1st Manassas (July 21, 1861.) A disorganized army, more a collection of regiments than an army, milled about Washington, D.C. and President Abraham Lincoln searched for a new commanding general of the Army of the Potomac to replace a discredited General Irwin McDowell.
Lincoln found Major General George Brinton McClellan, a general who had achieved some success in military operations in western Virginia. McClellan was young and brash, a gifted organizer, and familiar with the most current tactics of the modern European army.
McClellan soon shaped the Army of the Potomac into a formidable force of 100,000 men. Under McClellan’s leadership, the Army of the Potomac was honed into the best military force ever to have been assembled on American soil.
Once the army was prepared, McClellan grew cautious. Reluctant to take the Army of the Potomac into the field, McClellan resisted increasingly insistent calls by the President and the Secretary of War to conduct offensive operations against the Confederate army established outside of Richmond, Virginia.
Rather than confronting the defenses of Richmond, McClellan developed a plan to attack from the south, along the peninsula between the James and York rivers. In the spring of 1862, more than 400 ships and barges were used to transport the Army of the Potomac, its horses and supplies, well south of the Confederate capital.
McClellan’s slow and deliberate move from Fort Monroe, Virginia diminished the advantage of surprise he had achieved and allowed Confederate commanders to organize their defenses. The peninsula’s terrain did not allow room for maneuver and eliminated the federal advantage in manpower. An audacious plan soon became a slow crawl north. Eventually the army’s progress did bring it near to Richmond and advanced units of the Army of the Potomac could hear the ringing of church bells from the Confederate capital.
The peninsula campaign also returned Robert E. Lee to active duty. He replaced the able Joseph E. Johnston, wounded in one of the many skirmishes on the road to Richmond. Lee’s attributes as a general seemingly bewildered McClellan. Audacious and offensive-minded, Lee confounded accepted military tactics. He divided his numerically inferior army and went on the attack, directing his men and horse in a series of brilliant maneuvers.
By the end of the Seven Days’ Battles, McClellan and the Army of the Potomac had been driven back to the safety provided by the guns of the Union navy at Harrison’s Landing, Virginia. Richmond would not see a significant force at its gates until General Ulysses S. Grant brought the Army of the Potomac to its northern outskirts in the spring of 1864.
McClellan’s command was diminished significantly when three corps were transferred to the command of General John Pope. McClellan and his reduced force returned to Washington, D.C. and McClellan’s organization abilities again served the Army of the Potomac well. When Pope’s Army of Virginia was decisively defeated in the Battle of 2nd Manassas (August 28-30,1862), Pope was relieved and McClellan once again charged with the conduct of war in the eastern theater.
General Lee’s success in relieving the threat to Richmond and his victory at 2nd Manassas led to the authorization from Jefferson Davis to conduct offensive operations. Lee’s plan was to march into Maryland and encourage that slave-owning border state to enter the Confederacy, to cut railroad access to Washington, D.C., and to relieve the worn torn countryside of Virginia. The Confederate government knew as well that a successful offensive would support its efforts to achieve diplomatic recognition of its independence from the European powers. The confederate offensive and presumably its success was also expected to disrupt the mid-term elections in the north and weaken Lincoln’s ability to prosecute the war.
Lee’s plan of invasion once again violated accepted military practice. He went on the offensive with a numerically inferior force and split his army into separate lines of advance. The strategy required excellent and reliable communication and Lee’s offensive was compromised significantly by the loss of Special Order 191 – an order outlining in detail Lee’s plans for the Maryland campaign and the disposition of his forces.
Lee’s Special Order 191 was soon given to McClellan who received it with disbelief. Though he knew of Lee’s advance into Maryland, McClellan would not believe that Lee had gone on the offensive with an inferior force. Accepted military tactics for the day presumed that an army on the offensive would hold a 2:1, if not a 3:1 advantage in force over the enemy. If Lee acted as McClellan would have acted, then Lee’s invading army should have numbered nearly 180,000 men, rather than the 60,000 that he led from Virginia. The finding of the orders, a windfall of exceptional proportion, was so extraordinary that McClellan was inclined to dismiss the intelligence as “disinformation” meant to confuse the federal army trailing Lee.
Finally overcoming his caution, McClellan took advantage of the intelligence gleaned from Special Order 191 although he wasted nearly 18 hours before pushing the Army of the Potomac into action.
McClellan found Lee’s nearly reunited army at Sharpsburg, Maryland, trapped with the Antietam Creek to its rear. What followed was the most horrific battle yet fought in North America. On September 17, 1862, the two armies collided. By day’s end, 12,401 men or twenty-five per cent of the Army of the Potomac had been killed or wounded while Lee’s Army of Northern Virginia had lost thirty-one per cent of its total effective force (more than 10,000.)
Both armies, significantly bloodied, consolidated positions as night fell. Lee’s offensive could not be sustained and he began the slow movement of wounded back to Virginia. Eventually his entire army crossed the Potomac river back into Virginia with little pursuit from the Army of the Potomac.
President Lincoln and others urged McClellan to challenge Lee’s retreat. Lincoln rightly noted that a decisive victory required the destruction of the Army of Northern Virginia and not merely the end of Lee’s offensive. McClellan argued that the Army of the Potomac required fresh units and the replenishment of supplies destroyed in battle. He seemed unwilling to acknowledge that Lee’s army was similarly impaired and that the Army of Potomac’s superior access to men and supplies was an advantage that Lee did not share.
In the weeks that followed the federal victory at Antietam, McClellan failed to follow up upon his battlefield success. Increasingly frustrated demands for action were met with indifference until the president could no longer justify McClellan’s continued command of the Army of the Potomac. He was relieved November 7, 1862.
Major General George Brinton McClellan remained on active duty until he resigned his commission on election day, November 1864, after his loss to Abraham Lincoln as the Democratic party candidate for the presidency.
President Lincoln took advantage of the successful repulse of Lee’s Maryland offensive. He had already developed a draft of the Emancipation Proclamation but had set it aside when trusted advisors observed that to issue an order of emancipation in the midst of federal military reverses would appear to be an act of desperation.
The victory at Antietam gave Lincoln his first opportunity to make public the Emancipation Proclamation, September 22, 1862. Crafted as a military measure and designed to deprive the Confederate government of the resources the Confederacy’s slave-based economy generated, a federal stance establishing the end of slavery as a military goal of its armies during the Great Rebellion served to effectively end both British and French interest in supporting the independence of the Confederate States of America. The Emancipation Proclamation became official, January 1, 1863.
Although General McClellan had failed to exploit his victory at Antietam, President Lincoln used the victory to gain diplomatic advantage as well to incorporate the abolition of slavery as a strategic aim of the Union’s military efforts. Lincoln transformed the Army of Potomac’s bloody victory in Maryland, September 22, 1862, into a singular and decisive achievement.
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