History Learner
Banned
Largest problem with John Bell Hood is theat he is one of the best military examples of the Peter Principle: In a hierarchy every employee tends to rise to his level of incompetence. To count on him to effectively command an army is near ASB - and to give him some credit, the pathetic soul knew it.
IIRC, a lot of Hood's issues late war were due to his medications. A single lucid moment at Spring Hill is all required for his part in this, in that thereafter he can proceed exactly as IOTL in that he goes to Nashville and then entrenches while doing nothing else. After Schofield's destruction and the first inklings of disaster in Georgia reach Washington, it's likely Lincoln, Grant, etc will follow through with replacing Thomas with Logan with orders to immediately attack. At that point, no matter the qualities of Logan or Hood, dismounted cav and green infantry against entrenched veterans of equal numbers is not a ticket to success. Thereafter, slipping off into Kentucky is an obvious strategic choice, otherwise the Army of Tennessee gets used to help clear out the remaining Union garrisons now largely cut off.
Hood taking Nashville probably means he lets Cleburne lead the battle and stays home sick/wounded/etc. Chattanooga falling with encirclement of the Union forces does not mean the war necessarily ends early as another Union force can be moved into the area before all of Tennessee is lost, but it will likely extend the war and reinvigorate the South. Without a victory on Union soil I do not see Europe intervening, not unless there is a grand defeat in Virginia with Washington either in Confederate hands or besieged and its fall appearing imminent.
In the aftermath of Second Manassas, the British were preparing to intervene until Sharpsburg happened. In 1863, the Roebuck Motion was on the table and wasn't withdrawn until Gettysburg was learned of. The complete destruction of a Federal Army, somewhere in the vicinity of 40,000 strong, would be the largest victory to date of either side in the conflict and would definitely reignite interest of the European powers. Further, there are no forces that can be transferred to blunt further Confederates offensives in the aftermath; historically Washington had already detached elements of the Army of the Potomac for the relief effort. The AotP can't spare much more because Lee in the fall of 1863 was showing signs of and actually considering a movement into Maryland and the AotP was still recovering from Gettysburg. What was detached historically is also massively outnumbered by the Confederate forces in theater now.