Can one general make a difference?

Victor Davis Hanson thinks so. Want to know what Grant, LeMay, Patton, Kitchener, Montgomery, Ridgeway, Sharon, and Sherman have to tell us about Petraeus?

But has a single commander ever made much of a difference in almost instantly turning around an entire theater?
...in almost every war, on occasion a single general can so radically change the pulse of the battlefield that a political victory becomes possible where once the public thought it was utterly improbable.

Big boots General. Big boots.