What resulted from the Battle of Antietam?

Answer 1

It gave Lincoln the credibility to issue the Emancipation Proclamation, which kept Britain and France from helping the South. (It would have made them look pro-slavery themselves.)

Answer 2

This unexpected Northern win gave Lincoln the credibility to issue the Emancipation Proclamation without making it look like a desperate measure.

The Proclamation made it ethically impossible for Britain to aid the Confederates - a most siignificant outcome.

The battle also spelt the end for McClellan. Although he had won the battle, he failed to pursure and destroy the Army of Northern Virginia, which the whole of Lincoln's cabinet thought he should have done, and he was promptly replaced by Burnside.

Answer 3

McClellan's uncertainties and his hesitating behaviour prevent the Union to achieve a decisive victory.

Nonetheless Antietam resulted a positive strategical outcome because Lee decided to retreat from Maryland giving up his invasion's plan.

Answer 4

It gave Lincoln the credibility to issue the Emancipation Proclamation, which kept Britain and France from helping the South. (It would have made them look pro-slavery themselves.)