Not until the spring of 1862, after a growing clamor for action by Republican newspapers, members of Congress, and an increasingly impatient Lincoln, did McClellan lead his army of more than 100,000 men into Virginia. Here they confronted the smaller Army of Northern Virginia under the command of the Confederate general Joseph E. Johnston, and after he was wounded, Robert E. Lee. A brilliant battlefield tactician, Lee had been offered a command in the Union army but chose to fight for the Confederacy because of his devotion to Virginia. In the Seven Days’ Campaign, a series of engagements in June 1862 on the peninsula south of Richmond, Lee blunted McClellan’s attacks and forced him to withdraw back to the vicinity of Washington, D.C. In August 1862, Lee again emerged victorious at the second Battle of Bull Run against Union forces under the command of General John Pope.
The Battle of Antietam, a painting of a Union advance by Captain fames Hope of the Second Vermont Volunteers. More than 4,000 men died on September 17,1862, when the Battle of Antietam was fought.
Successful on the defensive, Lee now launched an invasion of the North. He hoped to bring the border slave states into the Confederacy, persuade Britain and France to recognize southern independence, influence the North’s fall elections, and perhaps capture Washington, D.C. At the Battle of Antietam, in Maryland, McClellan and the Army of the Potomac repelled Lee’s advance. In a single day of fighting, nearly 4,000 men were killed and 18,000 wounded (2,000 of whom later died of their injuries). The dead, one survivor recalled, lay three deep in the field, mowed down “like grass before the scythe.” More Americans died on September 17, 1861 when the Battle of Antietam was fought, than on any other day in the nation’s history, including Pearl Harbor and D-Day in World War II and the terrorist attacks of September 11, 2001. Indeed, more American soldiers perished at Antietam than in all the other wars fought by the United States in the nineteenth century combined.
Since Lee was forced to retreat, the North could claim Antietam as a victory. It was to be the Union’s last success in the East for some time. In December 1862, the Union suffered one of its most disastrous defeats of the war when General Ambrose E. Burnside, who had replaced McClellan as the head of the Army of the Potomac, assaulted Lee’s army, which was entrenched on heights near Fredricksburg, Virginia. “It was not a fight,” wrote one Union soldier to his mother, “it was a massacre.”