Why is the Antietam considered a turning point in American history?

Answer 1

The Battle of Antietam was the single bloodiest day of the American Civil War and is considered one of the major turning points of the war. ... The North was able to use the victory to raise morale, keep the South from gaining diplomatic recognition, and emancipate the slaves in the rebel states.

Answer 2

It was the Union victory that Lincoln had been waiting for, so that he could issue the Emancipation Proclamation without making it sound like a desperate measure.

This kept Britain and France from helping the South - Lincoln's biggest worry - as it would make them look pro-slavery themselves.

Answer 3

kept france and england from intervening