Richmond Must Fall to a Republican General
General George B. McClellan believed that the War against the American South should be “conducted according to the established usage of civilized nations,” not against civilians, and with an intent to minimize destruction and casualties.
Bernhard Thuersam, Chairman
North Carolina War Between the States Sesquicentennial Commission
"The Official Website of the North Carolina WBTS Sesquicentennial"
Richmond Must Fall to a Republican General:
“McClellan’s troubles began when some Democratic papers in early 1862 began touting him as a presidential candidate in 1864. This was not his doing, but it sealed his fate. The Republicans in Congress and the White House realized that they had a problem: Were McClellan to capture Richmond, he would pose a serious threat to Lincoln’s reelection. In other words, military victory in 1862 meant political defeat in 1864.
[The Republicans] could not demote McClellan, however: He was too popular and respected, and they had no reason they could give for doing so. Their only was out  of this dilemma was for McClellan and the Army of the Potomac to fail.  And it appears that Lincoln and his new Secretary of War, Edwin M. Stanton, deliberately sabotaged McClellan’s peninsular campaign.
….McClellan was right to advance on Richmond from the east, via the peninsula between the James and York Rivers, as opposed to the overland route favored by the [Lincoln] administration. It was shorter, had fewer natural obstacles, and could be supplied and reinforced easily by sea, but it was McClellan’s plan, and that doomed it.
At the outset of the campaign, the President, after assuring McClellan otherwise, transferred [General Louis] Blenker’s division to General [John] Fremont in the Shenandoah Valley; then he withheld [General Irvin] McDowell’s Corps (for the defense of Washington, he claimed).  That was 50,000 troops. A member of his staff told him: “General, the authorities at Washington are painfully afraid that you will succeed in taking Richmond, and therefore are stripping your army in the beginning.”
So, when the Seven Days battles commenced in late June [1862], McClellan, on the offensive, was outnumbered (101,000 to 112,000).  These engagements hardly amounted to the decisive repulse they are sometimes described as. McClellan’s command suffered fewer casualties than did the Confederates (15,849 to 20,614), little equipment or supplies were lost, and his new position on the James River was secure; with reinforcements, he could had resumed the offensive in August.
The President’s decision to terminate the campaign and withdraw McClellan’s army was not a military one. Gen. John Pope’s Army of Virginia was ready to march south. Richmond would be taken by a Republican general, or not at all.  Pope issued orders that essentially authorized the plundering of civilians and the destruction of property. The reign of arson and theft had begun.
When McClellan heard of the new policy, he was appalled and vowed never to carry it out: “I will not permit this army to degenerate into a mob of thieves.” He later sent a letter of rebuke to Lincoln: The war “should be conducted according to the highest principles known to Christian civilization. It should not be….a War upon population; but against armed forces and political organizations.”
(The Path Not Taken, H.A. Scott Trask, Chronicles Magazine, February 2006, (excerpt) page 33)