Jeffrey D. Wert, in his history of the Army of the Potomac, The Sword of Lincoln, examines the intricate relationship between Lincoln and his most difficult wartime commander, George Brinton McClellan:
“The enemy’s proximity to Washington and its defiance formed the background of a dispute, which mounted in intensity and in consequences, between McClellan and the administration. At its most basic level, it was an argument over preparations and timing. At its most significant level, it defined the relationship between a popularly elected government in a struggle for its existence and the role of its premier army in that struggle. Its two central figures were the army commander and the president of the United States.
“When McClellan assumed command in the aftermath of Bull Run, he had to strengthen the capital’s defenses and forge a weapon that could undertake field operations. He argued correctly that it would require time to accomplish both. On August 2, in a memorandum prepared at the request of Lincoln, he stated his strategic ideas and the requirements for victory. At the heart of the document was his assertion that the enemy had made Virginia ‘their battle-field – and it seems proper to make the first great struggle there.’ The Federal war aim should be a limited one – the restoration of the Union, while adopting ‘a rigidly protective policy as to private property and unarmed persons, and a lenient course as to common soldiers.’
“He had no doubt that victory would result only from the application of ‘overwhelming physical force.’ Such a force, ‘the main Army of Operations’ or his army, would need 273,000 men in 283 regiments of infantry, cavalry, and engineers and 100 field batteries. ‘It is perhaps unnecessary to state,’ he concluded, ‘that in addition to the forces named in this memorandum strong reserves should be formed, ready to supply any losses that may occur.’
“How deeply McClellan believed that he needed an army of such size is difficult to assess. He surely knew that the administration would need months, if not longer, to recruit, arm, and equip this ‘main Army of Operations,’ while also meeting the requests of commanders in other theaters. In turn, he would refuse to undertake a major offensive until he had an army of sufficient strength, armament, and training.
“McClellan supported his argument for a sizeable army with inflated estimates of enemy numbers. On August 8, he reported that Johnston had at least 100,000 troops in front of the Federals. Five weeks later, he placed the figure at 170,000, while his department had barely 80,000 officers and men. At the same time, he called Allan Pinkerton, the head of a detective agency, to Washington to conduct intelligence operations. By the end of September, Pinkerton, who used the name E.J. Allan, had twenty-four agents in the field.
“Together Pinkerton and McClellan submitted overestimates of Confederate strength, a pattern that would characterize McClellan’s tenure as army commander. Pinkerton deliberately overstated the number of Rebels, and McClellan knew it. On October 4, when the agent reported Johnston’s strength as 98,400, far less than the 170,000 that McClellan had stated earlier, the general did not forward this estimate to the War Department. ‘No other general,’ historian Stephen W. Sears has asserted, ‘exaggerated in such monumental proportions or for so long a period.’
“His assessments of enemy numbers defy logic. His reports painted a portrait of a ‘vast machine’ constructed by the Confederacy, although its white male population was only one-third that of the North. If the Lincoln administration could not marshal such manpower, how could the newly organized Davis government? McClellan, however, evidently believed his own reports, which provided him with a logical base for his strategic and command decisions. He could justify his unwillingness to advance against the Rebels until preparations had been completed. Likewise he justified his cautious tactics when he met the foe. But these overestimates could, however, cripple, if not paralyze, the army when an opportunity to strike arose.
“If the difficulties between McClellan and the administration had been only questions about numbers, readiness, and timing, they might have been resolved. But it went deeper than that, for McClellan had a record of quarreling with superiors and an abiding contempt for politicians. From his days at West Point through his years in the army, he had clashed ‘with anyone in authority,’ according to Sears.
“It is not surprising then that McClellan ignited a feud with Winfield Scott within days of his appointment. ‘The old man . . . cannot long retain command I think,’ he informed his wife on august 2. ‘When he retires I am sure to succeed him, unless in the mean time I lose a battle – which I do not expect to do.’ Six days later, after he had ‘a row’ with Scott – most likely over the adequacy of the capital’s defenses – he described the general-in-chief to Ellen: ‘I do not know whether he is a dotard or a traitor! . . . he is a perfect imbecile. He understands nothing, appreciates nothing & is ever in my way.’ Six weeks later, he wrote that Scott ‘threw down the glove & I took it up, I presume war is declared.’
“His letters to his wife during these months contain a litany of his troubles and also harsh descriptions of Lincoln and Cabinet members. At different times, McClellan called the president ‘an idiot,’ ‘a rare bird,’ and ‘the original gorilla, about as intelligent as ever. What a specimen to be at the head of our affairs now!’ Following a Cabinet meeting, he railed to Ellen: ‘I can’t tell you how disgusted I am becoming with these wretched politicians – they are a most despicable set of men & I think [Secretary of State William] Seward is . . . a meddling, officious, incompetent little puppy.’ As for Lincoln, ‘The Presdt is nothing more than a well meaning baboon.’
“McClellan’s antipathy toward political leaders reflected a common opinion within the professional military. He and fellow officers had seen the pernicious effects, as they thought, of political interference with the army in Mexico. Mcclellan was contemptuous of and condescending toward them. In his thinking, he was a general beset with a numerically superior force in front and an ignorant and obstructive government in the rear. ‘It is perfectly sickening,’ he wrote in another letter to Ellen, ‘to have to work with such people & to see the fate of the nation in such hands.’
“The army commander’s disdainful attitude festered and worsened over time. He failed to understand that the conflict was fundamentally a political contest. Campaigns and battles would derive much of their significance from their impact on public opinion. The war had begun in a boiling cauldron of politics; its resolution rested on the steadfastness of the political will of Northerners and Southerners.
“As Henry Hunt said, ‘Revolution devours her children,’ and revolution was afoot in the land. Its shape remained undefined, but it could not be limited. Like a swelling current, it would scour and establish new courses. The war tested, as never before, the military would be intertwined with politics. Blinded by his prejudices, McClellan refused to see that ‘the fate of the nation’ rested ‘in such hands.’ He was a soldier breasting a powerful stream.
“Despite his private, belittling descriptions of Lincoln, McClellan enjoyed the support of the president during the summer and fall. Lincoln conferred frequently with McClellan, joined the general at reviews of the troops, worked tirelessly to recruit and equip the army, and even defended the commander when others complained about the army’s inertia. He witnessed the disagreements between Scott and McClellan over the capital’s security and strategy. A patient man, Lincoln accepted McClellan’s argument for more men and more time.
“Lincoln, however, never lost sight of his greatest burden as president – to sustain his fellow citizens’ will to wage war against the Confederacy for as long as it might require and at whatever its cost. He had tapped into the outpouring of nationalism after Fort Sumter and had exploited the new resolve after the defeat at Bull Run, but he knew that it would not endure without success on battlefields. The foundation of the Union cause resided at isolated farmhouses, on dusty village roads, and amid the bustle of city streets. Military inactivity or stalemate could erode away some of that foundation.
“While the union war effort encompassed both the Eastern and Western theaters, most of the Northern press and populace focused on the Army of the Potomac. It had the primary burden of defending Washington. If the national capital fell, the Union cause would be no longer politically sustainable. In turn, the Confederate capital beckoned a mere hundred miles to the south as it had before Bull Run.. Although Federal successes in the West ultimately led to the collapse of the Confederacy, the war’s main battleground rested in Virginia. Here, the southerners had their best opportunity to secure a favorable political settlement with battlefield victories. Here, too, the Army of the Potomac, with the shadow of Washington upon it, carried more than any other union command, the political will of the North.
“Military necessity and political reality bound Lincoln to the Army of the Potomac. His almost unremitting attention to its operations reflected this tie. Its fortunes would be his. The relationship between him and its commander would be a central theme of the war in the East. In George McClellan he would find his most difficult subordinate. One of them believed the army belonged to him. The other knew it belonged to the country.”