Lee might have won the Seven Days’ Battles, but he was in trouble. McClellan was still sitting outside Richmond with a viable field army. Even though Stonewall Jackson managed to tie up a significant Union force in the Shenandoah he’d never possessed the ability to destroy it.
The disparate forces – Banks’, Fremont’s, and McDowell’s armies – were gathered together and put under the command of John Pope. This force was poised to move straight from Washington to Richmond, completely avoiding Lee’s Army of Northern Virginia in the process.
Lee had four things on his side.
The first was a concept used to great effect by Frederick the Great, one of the greatest generals in all of history. Lee, like the generals before and since, stood on the shoulders of giants. During the summer of 1862 Lee stood on the shoulders of Frederick the Great, Gustavus Adolphus, and Napoleon Bonaparte.
Firearms entered use in European armies in the late medieval period. By the Renaissance they were well established but not necessarily well used. Early hand guns, as they were called to differentiate them from field guns, were slow, inaccurate, and nearly as dangerous to their owners as their targets. Most handgunners were not equipped to face off against heavy infantry or charging cavalry and were handicapped compared to archers by the significantly reduced effective range of their weapons. Unescorted handgunners usually found themselves at a huge disadvantage on the battlefield.
Melee infantry continued to play a role on the battlefield. Armor was virtually useless against guns, so heavy infantry was replaced by light forces armed with long pikes who would form the first line of defense against cavalry. Cavalry changed, too. Knights disappeared, replaced by light, fast cavalry armed with sabers and, eventually, single shot pistols.
The first true revolution in the gunpowder age came in the early 1600s with Gustavus Adolphus of Sweden and the New Model Army. Matchlock muskets had replaced the primitive weapons of the Renaissance, allowing more consistent fire. Gustavus Adolphus was the first to see the advantages the new weapons provided and capitalize on them.
The main innovation he brought to the New Model Army was drill. Rather than unguided masses of gunners between a dozen and thirty ranks deep, Gustavus Adolphus reduced his ranks to three, allowing his forces to engage in a rolling advance. The third rank reloaded, the second rank prepared to fire, and the first rank fired. When the first rank fired the other two ranks could move up or the first could move back, allowing a continuous storm of fire and an orderly advance or retreat.
Gustavus Adolphus also re-invented combined-arms tactics. He mixed cavalry in with the infantry to allow quick exploitation of gaps in the enemy line. More importantly, he pioneered the use of light, mobile field guns to provide supporting fire at key points on the battlefield. He also intentionally held forces back in order to reinforce the line in the event of imminent breakthrough or breakdown.
About a century later Frederick the Great would take the next step forward in preparation for the Seven Years’ War. He refined the drill and got infantry marching in cadence. This allowed his troops to rapidly change formation, moving from route to battle formation far more quickly than previous armies.
He also made expert use of interior lines. During the Seven Years’ War Prussia was outnumbered and surrounded from the outset. The only reason Frederick the Great managed to hang on was because he was in a geographically small area surrounded by enemies who were spread out and not always moving in a coordinated fashion. The Prussian Army was able to move from one hotspot to another, then outmaneuver their enemies on the battlefield.
Frederick the Great was also the beneficiary of that most fickle battlefield ally: luck. At the moment it seemed that Prussia had finally run out of steam, Empress Elizabeth of Russia died and opposition to Prussia fell apart. Sometimes that’s what it takes, though.
The two main Napoleonic strategic innovations were also at play. These were the central position and the envelopment. Central position involved the concentration of power against a foe with superior numbers. If an inferior force can hold local superiority at key points, it can win the day. Envelopment is both a strategic and tactical move. It involved moving around the enemy’s flanks while cutting off communications and threatening stores.
In the summer of 1862 Lee had the advantage of interior lines when dealing with Pope and McClellan. This advantage only worked because of three other advantages Lee had: John Pope, George B. McClellan, and Henry Halleck.
Henry Halleck, as already discussed, was U.S. Grant’s boss out west who wanted Grant booted from the army. His star was on the rise in the summer of 1862 specifically because of the successes of his least-favorite subordinate. Lincoln believed Halleck had the answers the Union needed, so he brought him to Washington and put him in command of the Union armies. It turned out that with Halleck was no great general when his subordinates were terrible.
McClellan stayed put on the bank of the James River asking for reinforcements. Pope moved slowly towards Richmond, stopping to establish a supply depot at Manassas Junction. He was close to the site of the previous spring’s battle at Bull Run. As was often the case in the Civil War, the South called the battles by different names. To the Confederates that battle was known as Manassas.
John Pope’s Army of Virginia had just over 50,000 men. Lee had 55,000, making this particular engagement one of the few where Lee actually enjoyed an advantage in numbers. Lee’s strategic position didn’t actually allow him to take immediate advantage. Pope’s forces were strung out across northern Virginia and Washington was taking McClellan’s army apart a corps at a time and moving them up from the Peninsula to reinforce Pope.
Lee proceeded to break one of the most important rules in the book. He split his forces in half and sent Jackson around behind Pope to hit his supplies at Manassas Junction. Lee stayed with Longstreet to stay in front of Pope and give the impression the Confederates were going to stay on the defensive.
On his way to Manassas Junction Jackson attempted his own version of Napoleon’s central position. He fought his old opponent, Nathaniel Banks, at Cedar Mountain. This time it was Jackson who held the numerical advantage and he severely mangled Banks’ force. The battle and a heat wave pinned Jackson in place long enough for Pope to concentrate his forces. Jackson missed his chance to pull a Napoleon.
Confederate cavalry under JEB Stuart kept Pope distracted and the Army of Virginia couldn’t carry the attack to the heavily outnumbered Jackson. Eventually Jackson slipped through the Thoroughfare Gap and hit Manassas Junction itself. The Confederates destroyed what they couldn’t carry, then withdrew before Pope could react.
Jackson then fought a short battle at Brawner’s Farm and settled down at the edges of the old Bull Run battlefield to wait for Longstreet. Pope attacked Jackson with a roughly three-to-one advantage and managed to completely bungle the entire thing. He couldn’t send clear orders to Irvin McDowell and Fitz-John Porter about an attack on the Confederate right flank and neither man moved. Pope didn’t bother to follow up and ordered some additional feints that were beat back easily.
He then decided that he was on the verge of victory. Even the imminent arrival of Longstreet’s corps through the Thoroughfare Gap didn’t faze Pope. He decided Longstreet was there to cover Jackson’s retreat from the battlefield.
No one was more surprised than John Pope when Longstreet’s corps steamrolled the Union left flank on the morning of August 30. The Second Bull Run was a decisive Union loss.
Meanwhile, George McClellan was about ten or twelve miles away in Alexandria with about 25,000 troops from the Army of the Potomac. It’s widely believed that McClellan intentionally stayed out of the fight in an attempt to discredit Pope. McClellan was thin-skinned and a politician and he knew that if Pope lost the battle Lincoln would have little sympathy. What was left of Pope’s Army of Virginia was folded in to the Army of the Potomac, which was left under the command of McClellan. Pope was sent to Minnesota to fight the Sioux.
Lee once again had defeated a numerically superior force through superior strategy and tactics. He attempted to capitalize on the victory at Bull Run and set the stage for the single most important engagement of the Civil War.