In 1862 some European leaders considered supporting the confederates. how did the battle at Antietam change this?

The Battle of Antietam in September 1862 marked a significant turning point in the American Civil War, as it was the bloodiest single-day battle in American history and ended in a tactical draw. The Union's strategic victory provided President Abraham Lincoln with the opportunity to issue the Emancipation Proclamation, which reframed the war as a fight against slavery. This shift in focus made it politically risky for European leaders, particularly in Britain and France, to support the Confederacy, as it would align them with a pro-slavery cause. Consequently, the battle diminished the likelihood of foreign intervention on behalf of the Confederates, solidifying Union morale and international standing.