"Economy of Force: Allocate minimum essential combat power to secondary efforts."
"Mass: Concentrate the effects of combat power at the decisive place and time."
--US Army Field Manual 3-0, Operations, 2001
Mass and economy of force are intimately related principles of war. This article explores the characteristics of this relationship and how new warfighting concepts and capabilities--in particular, network-centric warfare--are likely to change that relationship and even the principles themselves.
Economy of force has the distinction of being one of the most misunderstood and unappreciated principles of war. (1) The confusion as to its meaning is no doubt because of the connotations of the word "economy"; in particular, most of us associate the idea of economy with reducing cost--that is, "economizing." Hence, some believe that the principle encourages operational commanders to use as little combat power as possible to achieve the mission--that the commander should be frugal.
However, as Bernard Brodie once observed, when originally propounded the concept meant "to suggest shrewd husbandry or usage" of military forces. (2) The commander was to employ effectively all available combat power--massing forces to achieve the primary objective while allocating minimum, but all necessary and essential, power to secondary tasks. Hence, the true sense of the concept is well stated in the US Army's doctrinal Field Manual 3-0, Operations: "Economy of force is the reciprocal of mass. It requires accepting prudent risk in selected areas to achieve superiority--overwhelming effects--in the decisive operation. Economy of force involves the discriminating employment and distribution of forces. Commanders never leave any element without a purpose. When the time comes to execute, all elements should have tasks to perform." (3) Carl von Clausewitz was also adamant that all forces be used:
If a segment of one's force is located where it is not sufficiently busy with the enemy, or if troops are on the march--that is, idle--while the enemy is fighting, then these forces are being managed uneconomically. In that sense they are being wasted, which is even worse than using them inappropriately. When the time for action comes, the first requirement is that all parts must act. (4)
Shrewd and Judicious Effects
Justification for employing all forces, and in a calculated or "shrewd" manner, arises from the numerous instances where commanders lost battles at least partly because they failed to do so. For example, in the American Civil War, General Robert E. Lee's Confederate army defeated General Joseph Hooker's Federal force at Chancellorsville in 1863 despite Hooker's large numerical advantage--half the Northern troops never engaged. At sea, the World War II battle of Midway in 1942 is instructive. The Japanese theater commander, Admiral Isoroku Yamamoto, commanded over 160 warships to Admiral Chester Nimitz's 76; but some of them, including two light carriers, were thousands of miles away carrying out a needlessly elaborate distraction scheme. (5) Arguably, if Yamamoto had massed more assets and more logically arrayed his total force, the Japanese would have won, despite the American signals intelligence advantage and strokes of luck. (6)
The straight fact is that massing forces is not always the best means to effectively employ them. Properly conducted economy-of-force operations can be just as important, or more so. For instance, an operational commander could "practice" economy of force in order to create opportunities. Traditionally, opportunities have been created by the shrewd and balanced dispersion of combat power; such dispersion can compel the enemy to do the same, or to at least adjust the disposition of his own forces. Ideally the enemy's response facilitates the execution of the commander's operational idea, making the main attack more effective by allowing a preponderance of combat power at the decisive time and place. …