 Porter in the post-war period never claimed to have made the statement and it also fails to note the several Union corps at that time defending Washington.Despite being a tactical draw, Antietam is considered a turning point of the war and a victory for the Union because it ended Lee's strategic campaign (his first invasion of the North) and it allowed President Lincoln to issue the Emancipation Proclamation on September 22, taking effect on January 1, 1863.Although Lincoln had intended to issue the proclamation earlier, he was advised by his Cabinet to wait until a Union victory to avoid the perception that it was issued out of desperation.