WI: Lincoln chose to follow McClellan’s original plan for the Peninsula Campaign.
George B. McClellan in 1862 wanted to end the war in one brilliant stroke. He was going to land the Army of the Potomac, over 120,000 men, in the Virginia Peninsula and advance on Richmond from the south. At the same time McClellan wanted McDowell’s 1st corps, 30,000 men, to advance on Richmond from the north. This would have given the Union a huge superiority in men roughly 150,000 soldiers to the Confederates roughly 55,000.
The reason Lincoln did not send McDowell’s Corps to the Peninsula is that politicians were pressuring him to deal with Stone Wall Jackson in the Shenandoah Valley.
McClellan may still have messed up the campaign, even with the extra men, since he’s so darn cautious, but he wasn't performing that bad during OTL. He devastated Robert E Lee’s forces at the Battle of Malvern Hill inflicting over 5,000 casualties on the Confederates. He easily could have sweep Lee’s army aside and taken Richmond especially if he had McDowell’s corps in support.
Is anyone out there confident that McClellan could get the job done with the extra troops?