Civil War Command: What Makes for a Good Corps Commander?

All too often studies of Civil War command are in reality studies of Civil War commanders. We know very little about how an army’s command system works, the responsibilities of command, and how command is exercised. For example, we don’t pay much attention to logistics and staff work, information gathering and battlefield communication.

I’ve had reason to contemplate these questions as I’ve written about commanders and command. I think one of the big reasons why Gettysburg turned out as it did was that for once the Union command system, even in somewhat ad hoc form, proved superior to its Confederate counterpart. In part that was due to the initiative of brigade commanders, and, all stories about Joshua Chamberlain aside, brigade commanders in blue were essential to the outcome of that battle, as were the performances of Winfield Scott Hancock and Gouverneur K. Warren.  Hancock seems to me to be a special case here, because he did not function as a corps commander during the battle (although he is often celebrated as the Army of the Potomac’s best corps commander, a ranking which might say something about the competition for that title, as Hancock’s performance in 1864 was a bit more mixed, although not all of that is due to him).

So, you tell me: what were the responsibilities of a corps commander, and who met those responsibilities best?