AGF Study, NO. 4: The Mobilization of the Ground Army

Section XXII


The foregoing narrative raises two general questions, which reach beyond the jurisdiction of the Army Ground Forces but on which its experience with mobilization may be of value to those responsible for military policy of the nation. One question relates to timing, the other to quantity.

As for timing, it is evident that more preparation of air and service forces in 1940 and 1941 might have produced a smoother mobilization in 1942 after the declaration of war. As seen in 1941, the 36 divisions mobilized before Pearl Harbor hardly seemed too many for an Army Aggregating 1,600,000, the strength attained at the end of 1941. But they proved to be far out of proportion as the Army developed. In 1942 emphasis continued to fall on divisions; 37 divisions were activated in that year alone. It was believed that corresponding nondivisional units could be activated somewhat later than divisions, since they required less time for training. This policy proved to have serious disadvantages. Activation of divisions and of supporting nondivisional units got out of step. Since the 1942 troop basis at first made too little provision for service units and since it developed that service units were in fact needed in the theaters before combat units arrived, many service units were activated in 1942 without troop basis authorization. Activation of service units became irregular, uncoordinated, and difficult to control. The troop basis, instead of forecasting mobilization, had to be changed repeatedly to authorize mobilization, ex post facto. At the same time, with divisions intentionally launched some months before their corresponding nondivisional units, future commitments for nondivisional units, especially service units, were continually built up. Thus the service program always seemed to be lagging; and to find manpower for service units many combat units were kept under strength for months after activation. Meanwhile the Air Forces were also rapidly growing.

The timing of mobilization depended directly on strategic plans. These were unstable in 1942. From March to August 1942 planning called for an invasion of northern Europe in conjunction with the British in April 1943. Rapid activation of divisions in 1942 was necessary to implement this plan. Then in the closing months of 1942 it was decided to confine ground operations in the eastern hemisphere to Northern Africa and to concentrate meanwhile on an air offensive against Germany. The date for invading northern Europe with land forces was indefinitely postponed. The mobilization objective for ground troops was reduced, and the rate of mobilization was slowed down. Two theaters were built up in the European area, each with a large requirement for overhead and service troops, though there was no ground fighting in the European theater until June 1944, and in the Mediterranean theater the number of United States divisions employed together in combat never exceeded half a dozen.

It is speculative to ask what would have happened had the plan to invade northern Europe in 1943 been carried through, had the mobilization of combat ground forces not been curtailed, and had the manpower productive facilities and ship space necessary to implement the bomber offensive and to maintain a number of partly inactive or secondary theaters been concentrated in a single invasion army. Invasion in 1943 would have lacked the incalculable advantage of prior assault by air. On the other hand, it would have had the advantage of being timed with German reversals after Stalingrad, with the German army overextended and on the defensive in the depths of Russia. Likewise it may be said that combatant ground forces were as large in April 1943 as they ever became later, though not so fully trained or organized into as many units as in 1944. Had invasion occurred in April 1943, means would probably have been found to increase the proportion of combatant ground forces within an 8,000,000 man Army. Coming in April 1943, major ground operations would have begun at almost exactly the same interval after declaration of war as they did in World War I. This would seem to have been at least theoretically feasible, considering that in World War II a head start had been gained by prewar mobilization. As it turned out, the United States was at war in Europe over twice as long in the second World War as in the first.


Combatant ground forces, virtually mobilized in over-all strength by the end of 1942, and thereafter improving their striking power by economy and reorganization within themselves, had a long period of waiting before commitment on a large scale. Except for two airborne divisions, no division activated after Pearl Harbor entered combat until 1944. For strategic plans as finally adopted, mobilization of ground forces was premature, and mobilization of air forces somewhat tardy. Decision to concentrate on strategic bombardment having been made rather late in the day, and the Air Forces continued to expand rapidly while the Ground Forces essentially marked time. All types of service units, some remaining from 1942, had to be formed in 1943 and 1944. Even so, it is difficult to understand why in the later period of mobilization, the period following 1942 in which the Army showed a net growth of almost 3,000,000 it was only air and service units and overhead establishment, not combatant ground forces, that expanded.

This leads into the question of quantity. It is a question of great national and international importance. The question is essentially this: How much power can the United States, considering all circumstances in its situation, actually deploy overseas on the ground?  How much force is exerted at the far end of the stick? If the United States, with 12,000,000 men in its armed services, including those under the Navy Department, can produce less than 100 divisions including those in the Marine Corps, this fact must be considered by all concerned in a future global war, and will certainly be considered by any possible enemies. The ability of the United States to conduct ground operations overseas was limited in World War II by a number of factors: by the amount of national resources needed to control the sea and the air, by policies of allowing resource to strategic bombardment and to the support of allies, by the need of maintaining long supply lines with streams of personnel and equipment constantly in transit over immense distances, and by the effort to provide American soldiers with something corresponding to the American standard of living. It was to the last two of these factors that the prodigious growth of service units and overhead was in large part due. These factors are likely to be always present. The strength of American ground armies is likely always to depend on the degree to which economy in these limiting factors is achieved.

How much such economy was achieved in World War II is too intricate a question to be answered without further study. Certainly the Army by the beginning of 1945 was a more economical and leaner organization than in any previous year of the war. Indeed the fat stored up in previous years proved to be a useful reserve. It was found that much could be dispensed with under pressure, such as a pool of soldiers on college campuses over half as large as the armored forces, comfortable surpluses of aviation cadets, and anti-aircraft artillery half as large as all infantry divisions combined, personnel engaged solely in post housekeeping duties, and allowances for margins of overstrength and for basic privates in tactical units. Somewhat tardily, since the necessary retraining had to be hurried, troops were converted to combat jobs.

These economies were mostly produced by emergency. Men saved by them were used mainly as replacements, going to maintain but not to increase the number of existing units. Maintenance of units at effective strength, as noted at the outset of this study, was a considerable achievement. If only for this reason, and apart from superiority of firepower, the 89 Army divisions overseas in 1945 were the equivalent of a larger number of enemy divisions. As for increase in number of combat units, all increase occurring after 1942 could be traced to economy with the Army Ground Forces rather than in the Army as a whole.

Smooth and economical mobilization, both in quantitative distribution and in timing, may well be impossible in any way, but if attained it would appear to require primarily two conditions. One would be a consistent strategic plan, in which successive phases of operations were foreseen well in advance and substantially adhered to. The other would be an authority able to judge between the claims of ground, air, naval, and service


forces, which with each engaged in its own business are unavoidable rivals and to apportion to each of them, in the light of strategic plans, such as a share of the national stock of manpower and resources as would assure to each the means for attaining maximum efficiency in its assigned role. Since no plan is infallible and no central agency omniscient, mobilization can never be perfectly smooth and perfectly economical. The problem is to find the best middle ground between rational foresight and short-run practical readjustments.



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