Many Europeans disliked the piecemeal approach under which Lincoln specified that only the slaves living in states that were then in rebellion would be freed. But it was difficult to argue against the Proclamation as a whole because the major European nations, with the exception of Portugal, had long since outlawed slavery and the slave trade. Lincoln had clearly put this in mind when he wrote the Proclamation.

Had Lee and the Army of Northern Virginia won the Battle of Antietam, the chances are that one or more of the European powers would have recognized the Confederacy as an independent nation. But because Lee lost the Battle of Antietam, and because of Lincoln’s Proclamation, the prospect for European intervention was dramatically reduced.