They were infinitely more important. In the U.S. military today, five members make up the Joint Chiefs of Staff, but they are followed up by hundreds, perhaps even thousands, of persons of general rank. In other words, barring the possibility of a nuclear exchange with some enemy, in a situation of conventional military combat, many, if not most, of those thousands of generals could step into the shoes of their commander, if he or she fell. This was not the case in the Civil War.

To begin with, there was no Joint Chiefs of Staff. There was the president and the secretary of war, and once one stepped from that lofty platform, leadership and command devolved upon a few individuals. Hooker, for example, as leader of the Army of the Potomac, had to account to no one except Lincoln and Stanton. In some ways that was a good, even a preferable, thing because he could therefore make swift decisions. But if something happened to Joe Hooker, the Army of the Potomac was leaderless. If something happened to Ulysses Grant, the forces converging on Vicksburg had to fall back. As true as this was for the Union, it was even more the case with the Confederates. Lee to some extent was the Army of Northern Virginia, just as Braxton Bragg was the Army of Tennessee.