George Brinton McClellan (December 3, 1826 – October 29, 1885) was an American military officer and politician who served as the 24th governor of New Jersey and as Commanding General of the United States Army from November 1861 to March 1862.

Early in the conflict, McClellan was appointed to the rank of major general and played an important role in raising the Army of the Potomac, which served in the Eastern Theater.

A major contributing factor in this decision was McClellan's failure to pursue Lee's army following the tactically inconclusive but strategic Union victory at the Battle of Antietam outside Sharpsburg, Maryland.

These associations gave McClellan what he considered to be an appreciation of the southern mind and an understanding of the political and military implications of the sectional differences in the United States that led to the Civil War.

He witnessed Scott's success in balancing political with military affairs and his good relations with the civil population as he invaded, enforcing strict discipline on his soldiers to minimize damage to property.

McClellan selected Yakima Pass (47°20′11″N 121°25′57″W / 47.3365°N 121.4324°W / 47.3365; -121.4324) without a thorough reconnaissance and refused the governor's order to lead a party through it in winter conditions, relying on faulty intelligence about the depth of snowpack in that area.

Upon his return to the United States in 1856, he requested an assignment in Philadelphia to prepare his report, which contained a critical analysis of the siege and a lengthy description of the organization of the European armies.

Although he complimented McClellan and expressed his "great confidence in your intelligence, zeal, science, and energy", he replied by letter that the 80,000 men would be better used on a river-based expedition to control the Mississippi River and split the Confederacy, accompanied by a strong Union blockade of Southern ports.

McClellan chose Rosecrans as his successor and briefed him on the situation before departing for Washington upon being summoned to reorganize the routed Union Army of Northeastern Virginia after the defeat at Bull Run.

Admirable self-denial!During the summer and fall, McClellan brought a high degree of organization to his new army, and greatly improved its morale with frequent trips to review and encourage his units.

For the first time, he revealed his intentions to transport the Army of the Potomac by ship to Urbanna, Virginia, on the Rappahannock River, outflanking the Confederate forces near Washington, and proceeding 50 miles (80 km) overland to capture Richmond.

Then, however, McClellan came under extreme criticism in the press and Congress when it was learned that Johnston's forces had not only slipped away unnoticed, but had for months fooled the Union Army with logs painted black to appear as cannons, nicknamed Quaker Guns.

Congress's joint committee visited the abandoned Confederate lines and radical Republicans introduced a resolution demanding the dismissal of McClellan, but it was narrowly defeated by a parliamentary maneuver.

Although McClellan was assuaged by supportive comments Lincoln made to him, in time he saw the change of command very differently, describing it as a part of an intrigue "to secure the failure of the approaching campaign".

As Swinton notes: It is possible, however—and there is a considerable volume of evidence bearing upon this point—that General McClellan, during all the earlier portion of the month before Yorktown, had it in his mind, even without McDowell's corps, to undertake the decisive turning movement by the north side of the York.

"[55] But McClellan was also tacitly acknowledging that he would no longer be able to invest Richmond, the object of his campaign; the heavy siege artillery required would be almost impossible to transport without the railroad connections available from his original supply base on the York River.

McClellan maintained his estrangement from Abraham Lincoln with his repeated call for reinforcements and by writing a lengthy letter in which he proposed strategic and political guidance for the war, continuing his opposition to abolition or seizure of slaves as a tactic.

[65] McClellan's reception in Frederick, Maryland, as he marched towards Lee's army, was described by the correspondent for Harper's Magazine: The General rode through the town on a trot, and the street was filled six or eight deep with his staff and guard riding on behind him.

[71] Still, historians—including James M. McPherson in Crossroads of Freedom: Antietam and The Battle Cry of Freedom, Stephen Sears in Landscape Turned Red, John Keegan in The American Civil War, and James V. Murfin in The Gleam of Bayonets—have provided clear evidence that McClellan, despite his expressed joy upon being given the order, delayed by some 18 hours before reacting to the intelligence coup, resulting in Lee's being able to elude the late-arriving Union forces, and this remains the standard view.

Despite significant advantages in manpower, McClellan was unable to concentrate his forces effectively, which meant that Lee was able to shift his defenders to parry each of three Union thrusts, launched separately and sequentially against the Confederate left, center, and finally the right.

[75] The battle was tactically inconclusive, with the Union suffering a higher overall number of casualties, although Lee technically was defeated because he withdrew first from the battlefield and retreated back to Virginia, and lost a larger percentage of his army than McClellan did.

As the war progressed, there were various calls to return McClellan to an important command, following the Union defeats at Fredericksburg and Chancellorsville, as Robert E. Lee moved north at the start of the Gettysburg campaign, and as Jubal Early threatened Washington in 1864.

McClellan worked for months on a lengthy report describing his two major campaigns and his successes in organizing the Army, replying to his critics and justifying his actions by accusing the administration of undercutting him and denying him necessary reinforcements.

McClellan supported continuation of the war and restoration of the Union, but not the abolition of slavery, although the party platform, written by Copperhead leader Clement Vallandigham of Ohio, was opposed to that position.

[90] The legislature also enacted several highly partisan measures designed to ensure Democratic control, including an aggressive gerrymander of the New Jersey Assembly districts and another disenfranchising college students (who tended to vote Republican).

[90] In addition to tax reduction, McClellan's economic agenda included the institution of a Bureau of Statistics of Labor and Industries and the creation of an agricultural experiment station to modernize growing and farming practices.

[99] McClellan himself summed up his style of warfare in a draft of his memoirs: It has always been my opinion that the true course in conducting military operations, is to make no movement until the preparations are as complete as circumstances permit, & never to fight a battle without some definite object worth the probable loss.

However, he died before it was half completed and his literary executor, William C. Prime, editor of the pro-McClellan New York Journal of Commerce, included excerpts from some 250 of McClellan's wartime letters to his wife, in which it had been his habit to reveal his innermost feelings and opinions in unbridled fashion.

First, McClellan proponents say that because the general was a conservative Democrat with great personal charisma, radical Republicans fearing his political potential deliberately undermined his field operations.

[106] Second, that as the radical Republicans were the true winners coming out of the Civil War, they were able to write its history, placing their principal political rival of the time, McClellan, in the worst possible light.