Logistics.
“An army marches on its stomach.”
— Napoleon Bonaparte“Amateurs study tactics. Professionals study logistics.”
— Omar BradleyErwin Rommel was a great tactician but a poor strategist.
During the invasion of France, his 7th Panzer Division was one of the most effective units in the field: he and Heinz Guderian were able to slip their army through a narrow gap in the Ardennes that had been left poorly defended by the Allies. They broke a bridgehead across the Meuse River at Sedan and then smashed into the French rear areas, encircling hundreds of thousands of Allied troops to the north, leading to the Dunkirk evacuation and the conquest of France and the Low Countries.
But he got lucky several times in a row to pull that off. Rommel moved so quickly that the “Ghost Division” outraced its own supply train and lost contact with headquarters, putting him beyond the reach of timely support in the event the French and British managed to rally. Had the Allied commanders been more on the ball, they could have easily cut him off and destroyed him. This same tendency to move too quickly is partly what ultimately led to the defeat of the Afrika Korps.
George Washington was a mediocre tactician, but a brilliant strategist.
George Washington fought around a dozen major battles in his military career, and lost half of them. He wasn’t a bad front-line battlefield commander (in his defense, he was almost always outnumbered), but he was far from the best even in his own time.
However, he excelled at seeing the larger strategic picture. Despite being outnumbered and out-supplied by his first French, then British opponents, he was a genius at maintaining the morale and cohesion of his army and conserving his own meager resources, as well as being very good at picking out which battles he actually needed to fight. He also understood the British Army very well, having fought alongside it during the French and Indian War. In this he epitomized Sun Tzu’s admonition that “If you know your enemy, and know yourself, you need not fear the result of a hundred battles.”
Most importantly, he understood how to translate his bird’s eye strategic perspective down to ground-level tactics and vice versa. He knew he didn’t need to defeat the British Army in a straight fight. The British Army had to defeat him to win. All he had to do was not lose: to keep his army in one piece and make the retention of the colonies too costly to continue the war.