Confederate General Robert E. Lee deals a stinging defeat to Union General John Pope at the Second Battle of Bull Run, Virginia—a battle that arose out of the failure of Union General George McClellan's Peninsular campaign earlier in the summer. Frustrated with McClellan, who was still camped on the James Peninsula southeast of Richmond, President Abraham Lincoln and General-in-Chief Henry Halleck decided to pull a substantial part of McClellan's Army of the Potomac and send it to General John Pope's newly formed Army of Virginia.
Lee correctly guessed that McClellan had no plans to attack Richmond, so he sent General Thomas J. "Stonewall" Jackson north to keep an eye on Pope's force. When it became clear that the Yankees were abandoning the peninsula, Lee moved more of his force northward to defeat Pope before reinforcements arrived.
The plan worked perfectly, and Jackson raided a major Union supply depot at Manassas, Virginia. Realizing that the Confederates were split, Pope began to pursue Jackson. But he could not find the Rebel force, which was hidden in the woods around Bull Run, the site of the war's first major battle more than a year earlier. Pope was confused, and issued contradictory orders that frustrated his troops, who marched back and forth for two days.
By August 28, Jackson knew that help was nearby in the form of General James Longstreet's corps. Jackson's men emerged from the woods and attacked a Union division late in the day, but the fighting ended in a standstill. On August 29, Pope attacked, but his army did not fare well. The Confederates mauled the Union troops, and by August 30 Pope had to retreat. His army lost over 16,000 men to the Confederates' 9,000.
Most shocking was the response of McClellan, now back from the peninsula. He was in nearby Alexandria, Virginia, and resisted sending a corps to aid Pope. Still smarting from the transfer of his troops to Pope's command, he "wanted Pope defeated," as Lincoln later wrote. But Lincoln could not remove McClellan for his treachery, because Lee soon began moving his army into Maryland for an invasion of the North.