For should the enemy strengthen his van, he will weaken his rear;
should he strengthen his rear, he will weaken his van; should he
strengthen his left, he will weaken his right; should he strengthen
his right, he will weaken his left. If he sends reinforcements
everywhere, he will everywhere be weak.
In Frederick the Great’s _Instructions to his Generals_ we read:
“A defensive war is apt to betray us into too frequent detachment.
Those generals who have had but little experience attempt to
protect every point, while those who are better acquainted with
their profession, having only the capital object in view, guard
against a decisive blow, and acquiesce in smaller misfortunes to
avoid greater.”