The American Civil War saw a revolution in new weaponry and tactics during its four years of combat. New weaponry curbed the use of full frontal assaults where brigades charged in double lines. The bloody assaults at Fredericksburg, Shiloh and Pickett’s Charge caused commanders from both sides to use the flank attack more often.
A flank attack is to attack an enemy or an enemy unit from the side. There are several variations to this basic military tactic. One type is employed in an ambush, where a friendly unit performs a surprise attack from a concealed position. Other units may be hidden to the sides of the ambush site to surround the enemy.
Another type is used in the attack, where a unit encounters an enemy defensive position. Upon receiving fire from the enemy, the unit commander may decide to order a flank attack. Part of the attacking unit “fixes” the enemy with suppressive fire, preventing them from returning fire, retreating or changing position to meet the flank attack. The flanking force then advances to the enemy flank and attacks them at close range.
The most effective form of flanking maneuver is the double envelopment, which involves simultaneous flank attacks on both sides of the enemy. This tactic was used extensively in the Civil War as commanders tried to outflank their opponent and bring concentrated fire or enfilade the enemy by firing along the long axis of the unit. For instance, a trench is enfiladed if the enemy can fire down the length of the trench.
Perhaps the most famous flank attack was Stonewall Jackson’s attack against the Union Army of the Potomac’s right flank at the Battle Chancellorsville on May 2, 1863. Robert E. Lee and Stonewall Jackson settled upon a highly aggressive plan to march Jackson’s forces around the Union positions and onto that exposed flank.
After a hard and dusty march on May 2, Jackson’s column reached its jumping off point for their attack upon the unsuspecting Federal right flank. At 5:20 pm, Jackson’s line surged forward in an overwhelming attack that crushed the Union Twelfth Corps. Federal troops, however, rallied, resisted the advance, and counterattacked. Disorganization and darkness ended the fighting.
Unfortunately for the Confederacy, while making a night reconnaissance, Jackson was shot by his own troops in the darkness and fell mortally wounded. Robert E. Lee was never able able to replace the great Stonewall and many historians maintain that his loss caused the defeat of the Confederacy.
On the Union side both Ulysses S, Grant and William T. Sherman used the flank attack to their advantage both in the Western Theater and in Virginia in 1864.
At the Battle of Missionary Ridge on November 25, 1863, Ulysses S. Grant planned a double envelopment of Confederate forces led by General Braxton Bragg. William T. Sherman leading 20,000 men from the Army of the Tennessee were to attack the right flank of the Confederate defensive line that was situated at Tunnel Hill. General Joseph Hooker with three divisions was ordered to assault the left end of the Confederate line.
Sherman’s assault on the right was stymied by a fierce Confederate defense but Grant ordered General George Thomas’ Army of the Cumberland to advance against the base of the ridge at the center of the Confederate defense.After taking the rifle pits the Union troops continued their advance and ultimately took the crest of the ridge. The Confederate lines were broken and Bragg was forced to order a retreat.
Sherman would go on to use the tactic of the flank attack throughout his advance to Atlanta. Sherman moved his forces along lines of least resistance and greatest gain. This approach guided the March to Atlanta, a series of interwoven flank maneuvers that included one precalculated frontal assault.
It was also the motivating idea in the Marches to the Sea and the Carolinas, which Sherman envisioned as a necessary ’roundabout’ flank attacks on General Lee in Virginia. Ironically, these marches over land, totaling over 600 miles, actually shortened the war considerably, perhaps by as much as a year.
When Grant took overall command of the Union armies his first campaign was dubbed the Overland Campaign because his intent was to move overland to Richmond. He planned to fight a constant series of battles against Robert E. Lee’s Army of Northern Virginia. His aim was the destruction of the main Confederate fighting force in the Eastern Theater.
The entire Overland Campaign was a series of flanking movements by the Army of the Potomac to force Lee to respond by moving southeast and eventually being brought to bay at Petersburg. Grant’s goal was to bleed the Confederates but in doing so he also bled the Army of the Potomac. Over the course of the campaign both armies had combined casualties of almost 89,000 killed, wounded, missing or captured.
Most of the casualties were sustained in the Wilderness (29,800), Spotsylvania Court House (30,000) and Cold Harbor (15,500). From May 5th until June 24th, the armies fought 11 battles, engagements and skirmishes. In the course of the fighting, the Union Army lost Maj. Gen. John Sedgwick, commander of the VI Corps, at Spotsylvania white the Army of Northern Virginia lost Maj. Gen. J.E.B. Stuart, their cavalry commander, at Yellow Tavern.
Finally, Grant’s overall strategy was to use the Army of the Shenandoah, Union forces in West Virginia and the Army of the James to attack the Confederate forces in the East on the flanks.
The Union forces in the Shenandoah Valley and West Virginia were assigned to deny Lee’s army of supplies from the rich farmland of the Valley. Ben Butler’s Army of the James was assigned to attack Richmond from the east and draw off troops opposing the advance of the Army of the Potomac. Most of these attacks would initially fail due to poor generalship. Eventually, Grant found the right generals to lead these efforts and they accomplished their objectives.