To be fair, the real turning point was Antietam. True, the battle was merely a draw, but it was enough to allow Abe to issue the EM.
More importantly, that battle kept France from declaring support for the CSA. Otherwise, France could have broken the Union Blockade, and the war would have ended differently.
The EM also prevented the British from declaring support for the CSA. It most probably would have been ships of the Royal Navy that broke the blockade it had come to that.