Respuesta :

"The Battle of Antietam was one of the most important events of the American Civil War. ... The battle ended the Confederate invasion of Maryland in 1862 and resulted in a Union victory. It also led to President Abraham Lincoln issuing the Preliminary Emancipation Proclamation on September 22, 1862."
     

      These are not my words, there from study.com  / hope this will help you
 

Answer:

Because of the bloodiest battle in the US History, Lincoln was able to issue the Emancipation Proclamation, which helped prevent France and Britain to recognize the Confederacy.

Explanation:

The battle of Antietam is know today as the bloodiest day in the history of the United States of America. It is calculated that there was a total of 22,717 dead, wounded, or missing in consequence of that battle. Somehow the Union was considered the winner, even though their losses weren't that different, giving Lincoln the perfect moment to write an executive order.