Actually, I believe that the Pope did recognize the Confederacy. I have seen the Crown of Thorns he had delivered to Jeff Davis, while imprisoned in Ft. Monroe, after the war. It is in the Confederate Memorial Museum in New Orleans.
Whoop-de-do. And I've read the account of the U.S. ambassador to the Papal States where he says the Pope's Secretary of State denies that His Holiness intended diplomatic recognition in his letter. Post-rebellion gifts to the contrary not withstanding.