Army Ground Forces Study No. 4
SUMMARY OF MOBILIZATION
Perhaps the largest generalization that can be made about the mobilization of combatant ground forces is that they were the first to be mobilized and the last to be used. Mobilization may be said to have begun in September 1940 with the adoption of Selective Service and induction of the National Guard. Until the declaration of war, mobilization and training were concentrated on combat-type ground forces. Air Forces remained relatively small, and service units were not produced in the proportions required for war, especially for a war conducted on the far side of oceans. In 1942 the emphasis remained heavily on the formation of new divisions. By the end of 1942 divisions and other ground combat units already mobilized had an enlisted T/O strength of 1,917,000. It was planned that this figure should reach 2,811,000 by the end of 1943.
At this time, in January 1943, the War Department expressed an intention to raise, through economies of manpower, the strength of ground combat units to a figure exceeding
3,000,000 enlisted men in 1944. Although mobilization had been in progress for over two years prior to the winter of 1942-43, no significant measures were adopted to economize manpower in the Army. There was now an ambiguity in the situation. Economy was now to the fore, but the need for adding to combatant ground forces had receded. Plans for invasion of northern Europe had been indefinitely postponed. Combatant ground troops moved overseas very slowly in 1943. Hence reserves accumulated in the United States. With the development of air power and with Russian victories, there was no certainty that United States ground forces would be needed in large numbers. Among the many demands for military manpower those of the Army Ground Forces were judged to be of low priority in 1943. In January 1943 the activation of three divisions was deferred from the first to the last half of that year. In June 1943 twelve divisions scheduled for the last half of 1943 (including the three deferred thereto) were deferred to 1944. But the War Department, while deferring divisions to 1944, did not defer to 1944 the attainment of the full strength of the Army. The troop basis of 1943 used up the full strength which the Army could expect to reach. This strength, including officers, was 7,700,000 after June 1943, when the ceiling was lowered from the 8,200,000 set in 1942. It was largely to accommodate the Army within the lowered ceiling that the twelve divisions were deferred in 1943. Despite lowering of the ceiling the Army in fact grew to a strength of over 8,200,000 as had originally been planned. Nevertheless, the deferment of divisions proved to be a postponement to the Greek Kalends, for the time never came when manpower was available for more divisions. The only hope of adding divisions in 1944 was the redistribution within the Army. Redistribution to divisions was not achieved, because the demand for overhead and replacements proved to be persistently in excess of estimates, because the increase of service units seemed impossible to check, and because certain combat requirements, such as the B-29 and heavy artillery programs, had to be met after the Army was already formed.
As a result, not only did the hope of raising ground combat strength to 3,000,000 enlisted men never materialize, but ground combat strength in the end hardly exceeded the strength already mobilized at the end of 1942. (See Table No. V.) On 31 December 1942, as noted above, T/O strength of enlisted ground combat units already mobilized was 1,917,000. Strength of such units mobilized on 31 March 1945 was only 2,041,000. T/O enlisted strength of divisions mobilized on 31 December 1942 was 1,056,000—on 31 March 1945 only 1,125,000. More units did exist in 1945 than at the end of 1942. Seventeen divisions were added in the first eight months of 1943, and almost 200 nondivisional field artillery battalions and over 150 engineer battalions in 1943 and 1944. (See Table VI.) But units were added without increase of total strength of ground combat units of all types. That is to say, the added units were not obtained by redistribution and economy within the Army as a whole, but by redistribution and economy within the combat elements of the Army Ground Forces. These redistributions and economies took the form of inactivation. With these inactivations and reductions the total strength of ground combat units in 1945 was approximately 1,000,000 below what had been planned in the winter of 1942-43. Combat ground forces grew to only two-thirds of their anticipated strength.
Although the total strength of combat ground units did not materially rise after 1942, the total strength of the Army rose by almost 3,000,000 after that date, increasing from about 5,400,000 to almost 8,300,000. These three million officers and men went into the Air and Service Forces, into nondivisional service units of the Army Ground Forces, into overhead in all forms, into the hospital population, and into organization of all kinds designed for the training and storage of replacements.
Thus in the Army of over 8,000,000 in existence in March 1945 only about one-fourth were combatant ground soldiers, not counting men currently in training as replacements, approximately 500,000, who would eventually join combat units but add nothing to their strength. (See Table I.) Excluding the Air Forces, which numbered 2,300,000, the strength of combat units was about 37 percent of the strength of the Army. Comparison may be made with World War I. In November 1918 combat ground forces numbered 1,660,000
officers and men, within 600,000 of the corresponding figure for 1945. If from the 1945 figure we deduct the antiaircraft artillery, which scarcely existed in 1918 and which in 1945 was not all used on the battlefield, the strength of ground combat units in 1945 was only 300,000 greater than in 1918. Ground combat units in 1918, numbering 1,660,000, constituted 45 percent of the total strength of 3,700,000 then carried on the books of the War Department. Excluding aviation, which in 1918 numbered 190,000, ground combat units constituted almost half the Army. Excluding both aviation and antiaircraft artillery, the Army put half its strength into combat forces in 1918, but only a third in 1945. (See Table I.)
Strength of ground combat units had not only fallen to 27 percent of the Army by April 1945, but according to plans then in effect for redeployment against Japan it was due to fall to less than 23 percent by December 1946. On 1 May 1945 General Stilwell, in a memorandum for General Marshall, called attention to the “disappearing ground combat army.” Copies of charts submitted with this memorandum are here attached as Annexes VII and VIII. The trend, wrote General Stilwell, “may be pregnant with disaster if we have a tough ground fight with Japan.” The Operations Division of the War Department, asked by General Marshall to comment, reviewed some of the main features of mobilization. It was noted that troop basis plans followed theater estimates of forces required. The continuing decline in the proportion of combat troops to the total Army, observed OPD,
is a natural result of a diminishing need in the actual numbers of assault troops due to mechanization of the Army, i.e., the great masses of armor airplanes that prepare the way for the final assault of the foot soldier with resultant saving of human life. While decreasing the actual number of assault troops needed in battle, these engines of war require a large and more extensive line of communication. The assault trooper is still the cornerstone of the offensive. However, mechanization had made him more efficient in the carrying out of his duties and he is not now needed in the great numbers formerly demanded when assaults consisted mainly of human blows against defended positions.
With due regard for the weight of this statement, it was nevertheless felt at the Headquarters of the Army Ground Forces that assault troops might be “more efficient in the carrying out of their duties,” and might be employed with more “saving of human life,” if certain advantages following from larger numbers could be obtained. One advantage in numbers was the ability to withdraw units before the point of fatigue at which casualties mounted. Another was the ability to concentrate decisive force at critical moments. A third was the ability to give systematic training, without the disruption and turnover within units caused by emergency demands. (See Study No. 12) In addition to numbers, there were qualitative considerations in the employment of manpower, treated at length in Study No. 5. Officers of the Army Ground Forces believed that casualties might be reduced if men of high caliber, both in physique and in intelligence, could be assigned liberally to combat units, where quick thinking and strong leadership might save not only a man’s own life but the lives of many others.
That aviation and mechanization, as noted by OPD, saved the lives of combat troops was not questioned by the Army Ground Forces. Indeed General McNair, especially in 1942 and 1943, had urged more attention to the air support of ground troops than he was able to obtain. (See Study No. 35.) But in Europe, despite extensive use of air and mechanized forces, infantry divisions had been required in larger numbers than had been planned. The same might conceivably recur in the Far East. In any case it was clear that success against Japan would depend heavily on the factors noted at the beginning of this study on naval and air power, and on the larger ground forces of foreign armies, in this case especially the Chinese, but also to an unpredictable extent the Russian, which at the least could be expected to neutralize certain enemy forces.
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Last updated 5 August 2005