In August 1862, Major General John Pope took command of the new Union Army of Virginia with orders to take the fight to the enemy, while George McClellan’s army moved by water to join him. Robert E. Lee had to strike before the two armies combined. This episode follows the Second Battle of Bull Run as a study in confirmation bias, beginning with Lee splitting his army and sending Stonewall Jackson on a march of roughly 50 miles in two days around Pope’s right flank to capture and burn the Union supply depot at Manassas Junction.

Jackson then hid his men behind an unfinished railroad grade on Stony Ridge and revealed himself at Brawner’s Farm, where John Gibbon’s Black Hat Brigade traded volleys with the Stonewall Brigade at about 80 yards. Pope convinced himself Jackson was retreating, sent in piecemeal assaults, disregarded John Buford’s report of Longstreet’s arrival, and issued a contradictory Joint Order to Fitz John Porter. On August 30, Longstreet’s 25,000 men struck the Union left in the largest simultaneous mass assault of the war.

• Jackson rode alone into an open field in a dusty plain uniform to count a passing Union column, then ordered his artillery to open fire.
• At Brawner’s Farm, about one in three men on the field was shot during more than two hours of standing volleys.
• Confederate brigades under Bradley Johnson and Leroy Stafford ran out of ammunition and threw rocks at the 24th New York, who threw them back.
• A rearguard on Chinn Ridge and Henry House Hill, ground from the first battle 13 months earlier, kept Pope’s army from total collapse.
• Pope was sent to Minnesota for the Dakota War, while Porter was court-martialed and not exonerated until the 1880s.