Central to the waging of war at the tactical level is the interplay between leadership and doctrine. Within a doctrinal context, the Army must develop leaders capable of winning the next war. This study examines the balance between leadership and doctrine and identifies the characteristics that distinguish the great leader from the also-ran. The vehicle for this examination is a comparison of two American Civil war generals, Stonewall Jackson and George McClellan. Purporting to support the same doctrine, the two men achieved remarkably dissimilar results on the battlefield. This analysis demonstrates that the reasons for that difference lay primarily in the realm of leadership rather than in the implementation of doctrine, and identifies the leadership principles key to success at the tactical level of war.