(July 5, 2017) Modern historians commonly condemn Union Major General George McClellan for almost uniquely overestimating the size of his opposing Confederate armies. According to the Civil War Trust, for example, the general’s “most grievous error [of] hugely overestimating Confederate numbers [was] a delusion [that] dominated his military character.” In truth, however, a number of Federal commanders were prone to overestimate the size of the enemy’s army.
During the Battle of Shiloh, for example, General Ulysses Grant sent a note to the commander of a reinforcing Federal army that Grant was under attack by more than 100,000 Rebels whereas the Confederates only numbered about 45,000. While that overestimation might be excused because it was made in the heat of battle, Grant continued to overestimate his opponents strength at 70,000 even after the battle.
Similarly, on the eve of the Battle of Antietam where McClellan would lead the Federal troops, Union General in Chief Henry Halleck in nearby Washington estimated Robert E. Lee’s opposing army at 150,000 men compared to its true strength of only 40,000. Nine days before the battle McClellan’s own commander of cavalry estimated Lee’s strength at 115,000. The prize for exaggeration, however, goes to Pennsylvania governor Andrew Curtin who wired the War Department five days before the battle that Lee had 190,000 men north of the Potomac River and another 250,000 men in northern Virginia ready to cross the stream. In short, Curtin estimated Lee’s army to be more than ten times bigger than it actually was.
As explained in an earlier post, President Lincoln was afraid that Stonewall Jackson would attack Washington following the latter’s repeated victories in the Shenandoah Valley in the spring of 1862. Even though Jackson had only 17,000 soldiers Lincoln estimated it at 30,000. Union commanders in the Valley, James Shields and Charles Fremont, estimated Jackson’s numbers to range from 20,000 to 60,000.
When Major General Jubal Early led a Confederate army in a second Shenandoah Valley campaign two years later and did, if fact, reach the outskirts of Washington, Lincoln’s War Secretary Edwin Stanton claimed Early’s army contained 35,000 men. In reality, Early had only 12,000.
Shortly before launching his offensive against Robert E. Lee at Chancellorsville in May 1863 Union commander Joseph Hooker told Lincoln that Lee outnumbered him, whereas Hooker actually outnumbered Lee two-to-one.
The prevailing tendency among historians is to judge McClellan for what he did not do as opposed to what he did. Thus, he is not admired for accomplishing in a matter of three weeks the transformation of a defeated Union army into one that stopped Robert E. Lee’s first invasion at Antietam. He is not applauded for immediately cancelling the orders of Stanton and Halleck to ship the weapons in Washington’s arsenal to New York and keep a steamer ready to evacuate political leaders in the panicked aftermath of Second Bull Run. Nor is he credited with earlier reaching the gates of Richmond before the Battle of Seven Pines by suffering only modest casualties and inflicting more casualties on Lee than Lee did on him during the ensuing fighting on the peninsula. Two years later, Grant would sacrifice over sixty thousand soldiers to put Petersburg under siege and force the surrender of the Confederate capital. Grant’s maneuver was much like the one proposed by McClellan in July 1862 but overruled by then General in Chief Halleck.