During the campaign, McClellan promised to do a better job than incumbent U.S. President Abraham Lincoln in prosecuting the Union Army effort in the American Civil War. The McClellan-Pendleton ticket eventually lost to Abraham Lincoln and former U.S. Senator Andrew Johnson's National Union ticket. After the election, McClellan was given command of all the forces in the western part of the country, which included his old corps. He set about organizing these troops and bringing them up to strength, while at the same time trying to restore their morale after their defeat by Lee.
When news of General Lee's surrender reached the west on May 10, 1865, thousands of Union soldiers celebrated late into the night by marching through the streets of major cities like Louisville, Kentucky and Richmond, Virginia. Others went on drinking sprees or hung around saloons waiting for news of their friends or relatives who were still missing after the battle. Some men behaved badly and committed crimes while they were joyous over the end of the war. These events contributed to a sense of relief but also great disappointment among the Union army veterans because they knew that many of them would never return home.
McClellan tried hard to keep up morale among the soldiers under his command. In early June he traveled to Washington City with his wife Ellen and two children to meet with President Lincoln.
To face Lee's threat, Lincoln delegated command of his main force to Maj. Gen. George B. McClellan, whom he deeply distrusted. Furthermore, the president had a significant stake in the next battle: only with a success could he carry out his goal to make the fight to preserve the union also a struggle against slavery. McClellan, by contrast, had no interest in engaging the enemy unless you can win, which was not Lincoln's way.
Lincoln believed that if anyone could beat Robert E. Lee it was George B. McClellan. The president knew that McClellan was arrogant and opinionated but he also knew that he was one of the best military commanders in America. By putting him in charge of the army, Lincoln was willing to take a chance on the future general getting things done. If things didn't work out, then he would be ready to replace McClellan with someone else. But for now, he needed someone responsible who could lead our army into Virginia.
McClellan's arrogance got him into trouble early in the war. After winning the Battle of Bull Run (which we called Manassas) against the Army of Virginia led by Robert E. Lee, he refused to believe that he had been defeated by an inferior force. Instead of pressing his advantage and advancing onto Richmond like the president wanted, he decided to retreat back to Washington, D.C..
George McClellan was a Civil War major general in the United States Army, railroad executive, and politician. After the Seven Days Battles in 1862, McClellan's Peninsula Campaign imploded, and he also failed to decisively defeat Robert E. Lee's Confederate Army at the Battle of Antietam. Instead, McClellan retreated back to Washington, D.C., where he became unpopular with the army and civilian population for his alleged arrogance and lack of initiative.
At the direction of Lincoln, who wanted a more aggressive commander for the war effort, McClellan was removed from command in September 1862, after which time he spent most of his time in political life.
Antietam is the bloodiest single day in American history, with 23,000 casualties estimated by historians. It has been called the "Crucifixion of America" because it revealed the deep divisions between Northern and Southern sympathizers and prompted Lincoln to issue the Emancipation Proclamation. McClellan's removal as commander contributed to these divisions becoming wider after his unsuccessful campaign.
The battle took place on Maryland's Eastern Shore near Antietam Creek near Sharpsburg. The town is now a national historic site. McClellan had chosen this location in hopes of defeating the Confederacy's entire army but knew that if he were to have any chance of winning the war he needed to attack Lee's larger force.