James Ford Rhodes (18481927). History of the Civil War, 18611865 1917.
Not only was McClellan working with diligence but everyone else was coöperating with him in a way to give his talent for organization the widest scope. The President, the Treasury and the War departments, the Secretary of State, the governors of the Northern States assisted him faithfully with their full powers. The officers under him displayed zeal and devotion. He had the sway of a monarch. And at the outset this complete harmony yielded results of a most encouraging nature. Troops poured in from the enthusiastic North, swelling the army of 52,000 of July 27 to one of 168,000 three months later.
One of McClellans limitations, however, came early into view. Although personally courageous, he feared reverses for his army. Moreover, either his intelligence of the enemy was defective or his inferences from such accurate information as he possessed were radically unsound. In August, he was haunted by the notion that the Confederates largely outnumbered him; that they would attack his position on the Virginia side of the Potomac and also cross the river north of Washington. At this time, however, Johnston did not purpose either movement; he was chafing at the smallness of his force, the lack of food and ammunition, the disorganization and sickness amongst his troops. During the month of September and well into October, he was encamped about Fairfax Court-house with strong outposts on hills six and a half miles from Washington, where the Confederate flag could be plainly seen by the President and his General. On October 19, he withdrew his army to Centreville and Manassas Junction, farther from Washington but a much stronger position.