With that said, would it be more of a possibility that Philadelphia would have been the city in question instead of Baltimore? As you posted earlier Non-Sequitur (at least I think it was you), this would have been assuming that a lot of things happen before and even during Gettysburg and your comment that the South was simply delaying the inevitable anyway.
As you study the Civil War don't get fixated on the east. Sure that's where the best known battles were and where Lee was and where the outcome wasn't clear until the end. But if you look to the west, you'll see a theater where the confederates almost never won a battle. Where they lost territory litereally from day one, and where the rebellion was basically decided. I've got a book from Kendall Gott titled "Where The South Lost The War" and his premise is that the deciding battle was Fort Henry/Fort Donelson in February 1862. Taking the forts opened the Tennessee River. The Tennessee gave the Union transportation into the heart of the state and points south, and aided in taking Nashville and Memphis. This led to the fall of the entire river, cutting the confederacy in half. And on, and on. Regardless of whether you accept his premise or not, it is clear that the South began losing in the west from the very beginning and that doomed the confederacy to defeat from the start.