Even though the outcome of the war was clearly in complete Union victory by this late date, the fall of these two important Confederate cities with a week of each other very clearly put any hope of a new nation completely out of the question.
The other dual Confederate disaster would have to be considered the loss at Gettysburg July 3, 1863, and surrender of Vicksburg the following day. This was the turning point.
But the fall of these two Atlantic ports was clearly the death knell.
No Hope. All is Lost. --Old B-Runner