An undated photo of Gen. George B. McClellan. (MATHEW B. BRADY/ASSOCIATED…)
On Sept. 17, 1862, Gen. George B. McClellan stopped Gen. Robert E. Lee’s first Confederate invasion of the North at the Battle of Antietam, the bloodiest day of warfare in American history. This narrow victory changed the course of the war.
Yet history has not been kind to McClellan. Politicians from the 1860s onward and countless historians have claimed he could have easily destroyed Lee’s army during the campaign and ended the war in 1862, sparing the country another two and a half years of bloody conflict.
Their criticism stems from the belief that McClellan moved too slowly and cautiously to attack Lee. They assert that when a copy of Lee’s plans fell into McClellan’s hands, the Union general wasted precious hours before advancing. They declare that McClellan’s forces outnumbered his foe’s by more than two to one and by that metric alone, he should have decimated Lee’s army. They are wrong.
Contrary to what most of the literature will tell you, McClellan was not a hesitant fool. He did his best under challenging conditions.
Scarcely two weeks before the Battle of Antietam, he was a general without a command. He had once held sway over all the Federal armies, but during the previous six months every unit under his control had been transferred to other generals.
Most had been sent to reinforce Gen. John Pope as he fought Lee on the plains of Manassas. Pope, however, was thoroughly defeated, and his demoralized troops streamed back to the capital with the Confederates close behind.
In a moment of desperation, Lincoln returned the shattered remnants of Pope’s army to McClellan, hoping its former commander could reinstill the high morale the troops had possessed a year earlier.
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When McClellan took charge of the Union forces on Sept. 1, he inherited four separate armies, thousands of untrained recruits and numerous other small commands that needed to be made ready in a hurry. To further complicate matters, three of his senior commanders had been ordered relieved of duty, charged with insubordination against Pope.
Unbeknownst to the Federals, Lee had struck north into Maryland. The cavalry was the arm of the service most likely to discover Lee’s change of direction, but when McClellan took over, there was virtually none available to him.
On paper, McClellan commanded some 28 cavalry regiments. But the disastrous Manassas campaign had worn out the horses of almost half the Union regiments, while most of the remainder were stranded at Hampton Roads by gale-force winds. For the first week of the campaign, McClellan could only count on perhaps 1,500 cavalry from two regiments and a few scattered squadrons from his old army to challenge some 5,000 Confederate cavalry soldiers screening Lee’s army.
Despite these handicaps, in the week it took for Lee’s army to march to Frederick, McClellan’s army traveled an equal distance to redeploy on the north side of Washington. This was accomplished as he reshuffled commands, had his officers under charges reinstated and prepared to fill out his army with untrained recruits.
These new men, organized into 1,000-man regiments, would account for about a fifth of McClellan’s force at Antietam. Northern recruiting booths had only reopened in July, and the first of these regiments were not assembled in their home states until mid-August. Before officers learned how to issue orders or their men learned to follow them, they were sent by train to Washington and immediately marched to the front. They would learn how to fire a musket as they marched to battle.
In the second week of the campaign, Lee’s army suddenly left Frederick and marched west.
As McClellan’s army advanced on Sept. 13, Union soldiers stumbled upon a four-day-old copy of Lee’s orders in an abandoned rebel camp. Known as Special Order No. 191, this paper revealed that Lee had dangerously split his army into five parts. Three columns had converged on Harpers Ferry to capture the Federal garrison there, a fourth column was in Hagerstown, and a fifth column was acting as a rear guard near Boonesboro, Md. Historians have debated fiercely over when the Lost Order was delivered to McClellan.
In his landmark 1983 book, “Landscape Turned Red,” Stephen Sears asserts that McClellan verified before noon that the papers were legitimate, then exhibited his usual excessive caution and failed to move his army for 18 hours. To back up this theory, Sears cites a telegram that McClellan sent to Abraham Lincoln at “12 M” — which Sears says stands for meridian or noon — in which McClellan confidently informs the president that he has the plans of the enemy and that “no time shall be lost” in attacking Lee.