Davis didn't focus his army on defending Richmond and letting all of Mississippi go. Why do you think there are troops sent from Bragg and Beauregard in Mississippi in 1863?
You could say "but none from Lee", but there's a very wide gulf between not dropping everything else for a relief effort and abandoning it.
I'm not going to say whether or not Davis's decision was best in this thread, but I will point here (which talks about sending Lee's men west):
http://civilwartalk.com/threads/confederate-strategy-in-may-june-1863-the-what-ifs.10013/
Most of it is about sending troops to Tennessee rather than Mississippi directly, I fear, but its still relevant to the problems with trying to do something about Vicksburg in '63.
As for Holmes's role, I defer to the people more familiar with his record - I'm not impressed by it, but I don't know if what he had to work with would have been successful. His career has always struck me as south of mediocre without having any specific blunder to clearly define. Just disappointment and excuses.
I can't judge how reasonable the expectations on him were, so I won't try to say if he was incompetent or simply overwhelmed by a big task here. The Confederacy does not have enough troops to go around.[/QUOTE For the military stratagist in the crowd , how do you fight a three different wars with limited resourses?I said wars because that was what the Confederate govenment was doing by1863.Each one having to either to be won or at least hold that foe in check.Give me a war in which the victor with the same resources vs another with unlimited .They may win battles but in the end their only pray is ,as with the Confederecy,is that the people will tire and call the larger force home,aka Viet Nam