V Corps served as the Army’s right flank at the battle of Mechanicsville (Beaver Dam Creek) on June 26, where the Union army prevailed, and at the Battle of Chickahominy River (Gaines’ Mill) the next day. There, V Corps with additional troops lost to a force led by Confederate Gen. Robert E. Lee, who had recently taken command of the Army of Northern Virginia. Porter had served as Lee’s adjutant at the U.S. Military Academy at West Point in 1853-1854 when Lee was the school’s superintendent.

Despite the loss, Porter so distinguished himself at Chickahominy that he was rewarded for his “gallant and meritorious conduct” with an appointment as a brevet brigadier general in the regular army.

The last of the Seven Days Battles took place at Malvern Hill on July 1, with Porter’s unit comprising McClellan’s left flank. This was a U.S. Army victory, as Lee’s ambitious offensive was repelled by the Union’s superior infantry and artillery. On July 4, Porter was promoted to major general of the U.S. volunteers.

Despite superior numbers and several wins against the Confederates, the Army of the Potomac was at a disadvantage as it had been cut off from its railway supply line and it was losing ground as a result of Lee’s aggressive actions. These factors and others weighed on President Abraham Lincoln’s mind leading him to end the Peninsular Campaign to seize Richmond.

In August of 1862, the Army of the Potomac returned to Washington to engage in the Northern Virginia Campaign commanded by Maj. Gen. John Pope. Porter and his V Corps were engaged in the most important confrontation of that operation, the Second Battle of Bull Run (Battle of Second Manassas) fought from Aug. 28 to 30. This conflict took place in the vicinity of Manassas, Virginia, where the Confederates had been victorious at the First Battle of Bull Run on July 21, 1861. Manassas is located approximately 32 miles southwest of the center of Washington, D.C.

During the 1862 battle, communications problems led to a lack of clarity among the Union commanders regarding orders and tactics. It also appeared that Pope either lacked accurate surveillance data, or did not exercise good judgment in assessing the situation. In his 2021 biography, “Radical Sacrifice: The Rise and Ruin of Fitz John Porter,” historian William Marvel wrote, “Pope, who had been confused about the location of the enemy for days, still badly mistook Confederate dispositions, and he would cling persistently to that misunderstanding in the face of all contradictory evidence.”

Porter was aware that Pope wanted V Corps to, according to Marvel, “push forward into action at once ...” On Aug. 29, Porter received fresh information regarding the enemy’s strength and position, and concluded that the planned assault would likely prove futile. As Marvel wrote, “Finally, in a decision that would allow others to destroy his career, he called off the attack on his own responsibility …”

The next day, on Pope’s further orders, Porter sent his men into battle. V Corps took heavy casualties in what was ultimately a terrible Union defeat against the Confederate forces led by Maj. Gen. Thomas J. “Stonewall” Jackson and Maj. Gen. James Longstreet.

In the wake of his humiliation at Manassas, Pope sought to deflect blame. Angered by Porter’s decision not to attack on Aug. 29, Pope accused him of disobeying orders. This led to Porter being removed from command on Sept. 5, 1862, to await results of a planned inquiry into his conduct at Manassas.

Next week: Maj. Gen. Fitz John Porter returns to duty, but will soon face a court martial.