William Swinton, Campaigns of the Army of the Potomac

The conduct of a commander should be judged from the facts actually known to him; and these were the facts known to General McClellan. Nevertheless, I make bold to say (and in doing so I think I am seconded by the opinion of a majority of the ablest officers then in the army¹), that General McClellan should have renewed the attack on the morning of the 18th. This opinion is grounded in two reasons—the one, general in its nature; the other, specific and tactical.

If it is possible to imagine a conjuncture of circumstances that would authorize a general to act á l'outrance and without too nice a calculation of risks, it is when confronting an enemy who, having moved far from his base, has crossed the frontier, and being foiled in his plan of invasion, is seeking to make good his retreat. This was the situation of Lee. He was removed an infinite distance from his base; his plan of campaign had been baulked; his army, reduced to half the effective of that of his opponent, was in a condition of great demoralization, and he had a difficult river at his back. McClellan stood on his base, with every thing at his hand, and his troops, doing battle on loyal soil, fought with a verve and moral force they never had in Virginia and could be called on for unwonted exertion.

But in addition to these considerations there is a special reason that promised a more successful result of an attack on the 18th than that which had attended the action of the 17th. The battle-field was by this time better understood; and notably General McClellan had had his attention directed to that commanding ground on the right, before mentioned, which formed the key-point of the field; but which, strange to say, had been overlooked the day before. It was proposed to seize this point with a part of Franklin's corps; and had