Why did George McClellan fail to act?

I think McClellan has been unfairly treated by the politicians in power and by history. (Republicans ran the government at that time and McClellan was a big name Democrat).

When he fought against Lee in the peninsula his army was close to the size of the confederates. In the peninsular campaign his strategy was altered without warning by Washington several times. He had a large force that was trained to land farther up the peninsula and block in the confederates on the peninsula while a large portion of his army come up from the south. Was great idea until Washington held back the large corp that was to do it. They then said they would send troops overland and ordered McClellan position himself in an awkward way to meet those troops. He had plans made in case of an attack by the now numerically superior Confederates from this position ordered by Washington to move their supplies and supply lines to the James River. The Confederates did attack and McClellan did move to the James River.

Remember Confederates counted their troops as soldiers in line for battle not everyone in the area while Union forces were counted as total soldiers in the area under command of that general. The Confederates had in place conscription and were rapidly building up their forces at this time while the Union shut down recruiting and told McClellan he must make due with what he had. No wonder he was careful with his soldiers.

Once on the James River he wanted to move across the river and attack Petersburg which would then force the Confederates to abandon Richmond. Washington would not allow him to do this. The best and possibly only way to keep a large Union army supplied around Richmond is by water. All this same stuff was done by Grant later in the war.

After General Pope took command of all the Union troops and got routed at Second Bull Run McClellan was given back command. That he moved cautiously only made sense. Lee just whipped that same Union army so it would be stupid to rush back to attack Lee.

As for the lost orders being so advantageous. McClellan was maneuvering against Lee when they found those orders. One of the reasons some Confederate commanders said that McClellan did not rush and overwhelm two easily defended (by Confederates) mountain passes was that according to the lost orders which were several days old already they stated that Lee should have had more troops at or near those passes. Also McClellan was trying to manoeuvre his army to try and save over ten thousand union troops that were ordered to stay at Harpers Ferry by Washington against McClellan’s advice. He was not allowed to evacuate them earlier and add them to his army.

At Antietam McClellan did attack Lee. In hindsight he should have attacked before most of his own army was there for the attack but just remember he had far fewer Calvary to inform him of the confederate numbers and position and it was still not too long since Lee’s army had routed this very army that he now commanded when Pope was in charge. When he did attack most of his main corp commanders and some replacement commanders were killed or wounded and one commander (Burnside) especially would not attack on time despite repeated orders from McClellan. If the loss of the corp commanders and some of their replacements had not occurred things might have been very different.

Also note that Lee complained of close to twenty-five thousand stragglers that were spread all over. McClellan could not have known the extent of the number of lost soldiers due to straggling

Overall McClellan faced the confederates in battle with forces far closer in number and ability then later commanders like Burnside, Hooker, Meade, or Grant. He also when you calculated out Union versus Confederate casualties the best ratio of any commander fighting Lee. And finally he handled his army in a way that never gave Lee an opening to destroy part or all of it even when ordered into a bad position by Washington before the start of the Seven Days battles. Longstreet said it was fortunate that they removed McClellan as he was good and improving rapidly. He was one of the most beloved commanders if not the most beloved by that army during the war. That is usually a sign by the soldiers that they trust that someone and believe he is not Just getting them killed for no good reason.

One issue was his knowledge of the Confederate Army. Almost all of the good cavalry went with the South, and without scouts he was reduced to relying on Pinkerton for intelligence estimates. I doubt they were actually paid a fixed rate per Confederate soldier reported, but the result would have been about the same.

So, McClellan was advancing, relatively blind, against forces that were reported to be considerably larger than his own. More resolute generals than McClellan have had problems in those circumstances.

The question has puzzled historians ever since. It's hard to look anywhere other than McClellan's makeup, which has led to much psychoanalysis of McClellan.

He had immense administrative ability. It's not too much to say that he saved the Union, with his formation of the Army of the Potomac after Bull Run. His Peninsula Campaign came within 4 miles of Richmond.

But it's also true that McClellan was strangely timid when it came time to force the issue. He wasted countless opportunities, seemingly stalled by insubstantial obstacles. He seemed to lack initiative. Plus Lee got completely into his head. It's difficult to imagine Grant stopping for a month at Yorktown, as McClellan did, rather than sweeping over it in his first couple of hours.

Ultimately no one knows. McClellan remains a complicated figure.