"But is was the politics of the day that it was overridingly important that Georgians command Georgia troops."
I'm aware of the desire to place commanders of troops with from the same state, however, in this case I question that assumption. Two of the other brigade commanders in Stevenson's division, Stephen Lee of South Carolina, commanded troops from Alabama, Alexander Reynolds of Virginia [50th Virginia Col.], commanded East Tennessee troops.
I believe there may have existed bad blood between Taylor and Jefferson Davis. Taylor had been appointed BGen from Kentucky Nov. 4, 1862, but the president declined to nominate and never forwarded his promotion to congress for approval.
[http://ehistory.osu.edu/uscw/features/regimental/kentucky/confederate/1stKentucky/taylor.cfm, Boatner's Civil War Dictionary]
05 12 1863 [Tuesday]
By the middle of the second week of May, as Grant’s resupplied army began its advance, the Confederates stood divided. On May 12 an engagement erupted at Raymond, fifteen miles from the Mississippi. In several hours of fighting, both sides sustained about five hundred casualties, but the outnumbered Rebels were gradually forced toward Jackson.
That evening Gen. S. D. Lee’s brigade moved towards Bovina arriving there the next day. (Swan, A Tennessean At the Siege of Vicksburg]
05 13 1863 [Wedesday]
The Yankees ˇturning in the direction of Jackson, we remained at Antioch Church until Wednesday 13th. The whole army of Vicksburg was put in motion, and it was evident that something was going to be done. We marched to Bovina station that day. (Spralding, 43rd Tenn., Reynold's Brigade)
Left Antioch, passed through Bovina, crossed the R. Road some few/four miles from Edwards Depot. (Reynold's Brigade)
General Cumming, in accordance with an order dated May 1, 1863 [would love to see], had assumed command of the brigade led by Brig. Gen. Thomas Taylor, on May 13. During the battle of Champion Hill, Taylor served on Pemberton's staff. [OR S1, V24, p2, p104]
Although a Colonel, he [Taylor] was apparently addressed as BGen due to his position. I find the same true of Col. A. W. Reynold's where I have found a number of documents referring to him as a General. Although Pemberton refers to him as a Colonel serving on his staff at Baker's Creek and during the Vicksburg siege, Taylor signs his parole on July 5, 1863 as BGen. Confusing!
Why Stevenson/Pemberton would allow Cumming to relieve Thomas at this critical junction is a mystery. One just doesn't replace a known entity under these circumstances as you set off to meet Grant. Seems to me there had to be some over riding reason? Reynolds by the way, also had a checkered career in the old army.
Reviewing Tom Taylor's CSR cards we find two letters from officers of his brigade, writing on May 12, complaining that the Senate had refused to confirm Taylor as a Brigadier General, they pleaded that he be so promoted and retained in command of the brigade. Apparently they had just learned of Taylor's replacement.
Taylor appears to have had a spotty career in the army. His file also contains at least two previous letters in 1862 from officers pleading his case against charges against him. Also a February 17, 1863 letter, Taylor to Davis, responding to a complaint against him from a Kentucky soldier. Too faint to study these documents on-line. There are some 165 cards in his file.
His papers include a card with this info:
Captain of Cavalry, CSA
Lt Col. & Col 1st Ky Inf
Brigadier General (President declined to nominate)
Colonel of Cavalry (Tempy rank) Declines [Note, this on July 2, 1864 for duty in Department of Virginia]
Of interest, Pemberton was West Point Class of 37', Stevenson & Reynolds, 38', Barton & Cumming 49' and Lee 54'. I would not suspect, Taylor not being a fellow "ring knocker," would have been a factor.
Taylor's replacement and what part this may have played in Pemberton's defeat at Baker's Creek, seems like a worthy area of research.