More contemporaneously, Josiah Gorgas complained in his diary that Davis had waited until after the fall of Donelson to send Bragg and the Gulf troops to Johnston.
A potential POD is perhaps Grant's mid-January reconnaissance shakes Jeff Davis into action. That said, Bragg might drag his feet on the matter. He seemed convinced that Butler and Farragut's naval-army force was aimed at him and he did not feel safe in sending more than a regiment to Tennessee.
Assuming Davis had sent Bragg and his force to Tennessee in early January, could a modified form of Grant's strategy have worked? Bragg's and Floyd's forces are sent to Donelson, with G. T. Beauregard taking command there. If Donelson can be made any stronger, maybe it can be done at this point. Could Fort Donelson become an early Vicksburg?
Beauregard would certainly not make the mistake of surrendering the fort as easily as Buckner. Planning for any counterattack would not be as shambolic as that of Pillow, Floyd and Buckner.But I do not think that Fort Donelson could be a Vicksburg. Fort Donelson offers a good defensive position like Vicksburg. However, unlike Vicksburg, reaching and isolating Fort Donelson is not that difficult of a feat. What made Vicksburg so troublesome was that all avenues of attack involved major difficulty and constraints. Furthermore, if Nashville falls to an assault by Buell's army, then Fort Donelson has lost its purpose.
Another issue is Fort Henry. The fate of Fort Donelson determined the fate of Nashville, but Fort Henry was the only point stopping USN gunboats and army transports from moving into the Deep South states of Alabama and Mississippi. Once Fort Henry fell, the USN destroyed several supply-carrying steamers and terrified Southern civilians, officers and politicians. Most importantly, with the destruction of the railroad bridge south of Fort Henry, the Confederate inner line of communication is severed. Polk's force in Columbus and Hardee's in Bowling Green are completely incapable of supporting each other. Columbus becomes especially vulnerable to a siege as a force moving from Fort Henry to Humbolt will quickly sever its supply lines. Fort Henry's fall also opens the Tennessee River for a Union descent on Corinth.
In short, I think Fort Donelson can be held at least longer than historical. However, Fort Henry's fall is ultimately what forces the Confederates to retreat from Bowling Green and Columbus as historical. I think the best means of improving the viability of the twin river defenses is to:
a) not place Fort Henry on a floodplain. Seriously, the incompetence in building this fort is astounding.
b) build up Fort Heiman as a replacement for Fort Henry or at least as a proper fort. The ground upon which Fort Heiman was built dominated Fort Henry and was actually within musket range of the fort. If Fort Heiman falls, Fort Henry falls.
