Exactly what do you think Grant, from his HQ miles away, could have done to intervene? He was in command of the entire Union Army. Tactical command was Burnside’s. Grant had no means of knowing what the tactical situation was. Don’t forget that Burnside knew that the same colonel was drunk & hiding in the magazine during Longstreet’s attack on FT Sanders in Knoxville. It was Burnside’s operation & the blame for the failure rests squarely on him.There is plenty of blame to go around. Burnside. The drunk Colonel laying in bed as his troops attacked willly nilly. But as I understand it both Grant and Meade were on the battlefield. Saw what was happening and neither intervened. To do so would violate chain of command. IF SO there is not a place in Hell hot enough for either of them.
I know that military procedure regards chain of command as inviolate. To breach it is to invite chaos. However to stand by and let neglect result in needless casualties while simultaneously allowing defeat to snatch victory out of clueless attacking soldiers was criminal.