George McClellan was a U.S. Army engineer, railroad president and politician who served as a major general during the Civil War. McClellan was well liked by his men, but his reticence to attack the Confederacy with the full force of his army put him at odds with President Abraham Lincoln. In 1862, McClellan’s Peninsula Campaign unraveled after the Seven Days Battles, and he also failed to decisively defeat Robert E. Lee’s Confederate Army at the Battle of Antietam. Frustrated by McClellan’s cautious tactics, Lincoln removed him from command. McClellan would go on to mount a failed presidential bid against Lincoln in 1864, and would later serve as the governor of New Jersey.