In September 1862, Confederate General Robert E. Lee crossed the Potomac River to invade Maryland and Pennsylvania. He was met by Union General George McClellan. The resulting Battle of Antietam, fought near Sharpsburg, Maryland, was the bloodiest single-day battle in American history, with a total of 23,000 casualties. It was a Union victory only in the sense that Lee’s invasion was stopped. McClellan was later removed from command and was faulted for failing to act on what crucial opportunity? Discuss
Source: The Free Dictionary