Is it true that McClellan was dismissed from duty for failing to pursue Lee after defeating him at the Battle of Antietam.?

Yes, it is true that General George B. McClellan was dismissed from duty partially due to his failure to aggressively pursue General Robert E. Lee after the Battle of Antietam in September 1862. Although McClellan's forces won a strategic victory, his cautious approach and hesitation to capitalize on this success frustrated President Abraham Lincoln and other military leaders. This ultimately contributed to McClellan's removal from command in November 1862.