George McClellan (December 3, 1826 - October 29, 1885) was a major general during the American Civil War. He organized the famous Army of the Potomac and served briefly (November 1861 to March 1862) as the general-in-chief of the Union Army. After his military service, he was an unsuccessful candidate for President of the United States in 1864 and was later elected Governor of New Jersey.
Early in the war, McClellan played an important role in raising a well-trained and organized army for the Union. However, although McClellan was meticulous in his planning and preparations, these attributes may have hampered his ability to challenge aggressive opponents in a fast-moving battlefield environment. He chronically overestimated the strength of enemy units and was reluctant to apply principles of mass, frequently leaving large portions of his army unengaged at decisive points.
McClellan's Peninsula Campaign in 1862 ended in failure, retreating from attacks by Robert E. Lee's smaller army, without the planned seizure of the Confederate capital of Richmond. His performance at the bloody Battle of Antietam blunted Lee's invasion of Maryland, but allowed Lee to eke out a precarious tactical draw and avoid destruction, despite being heavily outnumbered. As a result, McClellan's leadership skills during battles were questioned by U.S. President Abraham Lincoln, who eventually removed him from command, first as general-in-chief, then from the Army of the Potomac. Despite this, he was the most popular of that army's commanders with its soldiers, who felt that he had their morale and well-being as paramount concerns.
General McClellan also failed to maintain the trust of Lincoln, and proved to be frustratingly insubordinate to the commander-in-chief. After he was relieved of command, McClellan became the unsuccessful Democratic nominee opposing Lincoln in the 1864 presidential election.
After the War, McClellan was elected as Governor of New Jersey, headed a railroad, and eventually became a writer. Much of his writing was in defense of his actions during the Peninsula Campaign and the Civil War.
Although the majority of modern historians assess McClellan poorly as a battlefield general, a small but vocal faction of historians maintain that McClellan was indeed a highly capable commander, and that his reputation suffered unfairly at the hands of pro-Lincoln partisans who needed a scapegoat for the Union's setbacks. Thus, his legacy defies easy categorization. After the war, Ulysses S. Grant was asked to evaluate McClellan as a general. He replied, "McClellan is to me one of the mysteries of the war."