Stonewall Jackson’s flank attack is hailed as the deciding moment of the battle of Chancellorsville, a blow which set the stage for the Confederate victory, and which represented Lee and Jackson at their finest. Perhaps, but it also represented Jackson’s continuing mediocre abilities as a tactician. The march did not maintain absolute secrecy; Union III Corps commander Daniel Sickles detected the movement and took appropriate action to disrupt it, catching the rear of Jackson’s column off-guard. Despite this though, Union HQ didn’t take the warning that seriously, but Howard was ordered to entrench and be prepared, just in case. He chose to ignore the orders.
Jackson’s alignment of his men for battle diluted the long-term effectiveness of his attack. The preferred method to maintain control and integrity of your units in the Civil War, as a division commander, was to deploy your brigades in two lines, which also gave you a reserve to exploit success. What Jackson did, and what Beauregard also did at Shiloh, was to simply deploy each of his divisions with all of it’s brigades abreast in one long line, with another division similarly arrayed behind it. This guarantees that your units are going to get intermingled and you’re not going to be maintain control of your forces. It required relatively little effort to deal the KO punch to XI Corps; Devens’ division and most of Schurz’s got knocked out pretty quickly. Von Steinwehr offered more of a fight, but was swamped by the Confederate numbers eventually. However, the force of Jackson’s attack was pretty much spent after this, against relatively little opposition. His men were stopped cold by entrenched XII Corps troops, and he made no further progress before his untimely wounding.
Let’s contrast Longstreet’s attack on Union forces, on May 6th in the Wilderness. Longstreet had two divisions, about 10,000 men. The force he was opposing was the II Corps of Winfield Scott Hancock; the corps had been diluted from it’s 1863 level of effectiveness by the injection of large amounts of entirely green units, but it was still a capable unit, and aside from Hancock himself, possessed two of the Army of the Potomac’s most capable division commanders, John Gibbon and Francis Barlow. They’d been involved in combat against A.P. Hill’s III Corps before Longstreet’s arrival, but were probably still around 20,000 strong.
When Longstreet arrived, Hill’s men were being swept off the field by Hancock. Longstreet counterattacked, and Hancock’s somewhat disorganized men were forced back. Then, Longstreet, upon being informed of an opportunity to flank the federals using an unfinished railroad cut, dispatched his most trusted aide to lead four brigades around and into the Union flank, while simultaneously resuming his main attack, now incroporating some of Hill’s brigades. In the words of Hancock himself, Longstreet rolled him up “like a wet blanket.” To do this, Longstreet deployed his men in heavy skirmish lines, which let them maneuver and strike through the difficult terrain while not presenting much of a target to fire back at. Had Longstreet not been hit by friendly fire, it’s possible he might have led his men to achieve a real tactical victory for the Confederacy. In any case, I contend Jackson’s flank attack was less impressive than Longstreet’s, and that in the terrain where Jackson achieved mixed results, Longstreet again demonstrated why he may have been the best general of either side for handling troops in battle. This isn’t intended to denigrate Jackson, who was one of the finest generals of the war at manoeuvring his forces when operating in an independent matter, but tactically, he was often at his weakest in the midst of a battle that had already been joined.