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June 18, 2025

Restoring the Primacy of Army Mobilization Planning: Lessons from the Interwar Period (1919–41)

Tim Devine
©2025 Tim Devine

ABSTRACT: This article argues that the US Army must restore the primacy of mobilization planning to prepare for the growing likelihood of a protracted large-scale war involving the United States. While the Army’s transformation initiatives have emphasized important tactical matters, this piece calls attention to critical strategic vulnerabilities associated with mobilization—one of the Army’s enduring core functions. The article identifies insights, challenges, and recommendations for contemporary leaders and practitioners by analyzing the body of thought on mobilization planning during the interwar period (1919–41) and drawing connections to the present day.

Keywords: mobilization, strategic planning, large-scale war, readiness, Interwar Period

 

Mantras about war fighting and large-scale combat operations characterize the Army’s transformation initiatives. Strikingly, mobilization—the process of marshaling a nation’s manpower and materiel resources for war—is not among the Army’s focus areas. Despite new emphasis on preparing for large-scale war, the Army remains out of practice with large-scale mobilization (a close companion to war fighting and large-scale combat). Fighting China or Russia, or a combination of authoritarian rivals that also includes Iran and North Korea, will quickly overwhelm the current force comprised of active, Guard, and Reserve soldiers. Considering its purpose has not changed—to fight and win the nation’s wars—the Army should restore the primacy of mobilization planning for the modern era of great power competition and potentially great power war.1

The body of thought on strategic planning during the interwar years (1919–41) captures why Army senior leaders should add mobilization to their transformation initiative without delay. Early mobilization plans from this period were rudimentary, but the Army gradually developed an ecosystem for strategic planning that improved product quality. Later plans reflected the intimate connections between the two “basic commodities” of mobilization—manpower and materiel—and accounted for the links in protracted large-scale war to arenas like public opinion, war plans, organizational design, military strategy and concepts, and national policy. By the eve of conflict, the Army—together with a community of interest across the military establishment, government, and industry—developed the first comprehensive strategy for generating a force upward of 8 million soldiers, 2.5 million vehicles, 90,000 tanks, and 42 billion rounds of ammunition to win the largest and most catastrophic war in history.2

“The conclusion seems inescapable,” summarized a former chief of military history when reflecting on the interwar years, “the United States Army must keep mobilization planning at the center of all its military planning.” While this is no longer the case, restoring the primacy of mobilization planning will allow the Army to fight and win in the tumultuous years ahead.3

Getting Started

The Army instituted mobilization planning following a suboptimal experience mobilizing for World War I. Veterans who later served as Chief of Staff of the Army, namely Generals John J. Pershing, Douglas MacArthur, Malin Craig, and George C. Marshall, were determined not to repeat errors they witnessed firsthand, for instance, as Marshall observed while assisting with mobilization operations in the United States and how the surge of recruits following the National Defense Act of 1916 and the Selective Service Act of 1917 beleaguered installations ill-equipped to handle large volumes of troops. The legislation assembled enough men into the Army and served as the basis for raising wartime units for the next 50 years, but conscripts often encountered poorly designed training programs, unqualified instructors, and inadequate facilities.4

Additionally, procurement of war materiel lagged, forcing American ground forces overseas to rely on foreign sources of supply. “Of the 10,000 75mm artillery pieces the War Department ordered,” historian Arthur Herman explains, “only 143 ever reached the front—and not one American-made tank.” While industry produced mountains of supplies and equipment that eventually became war surplus, at issue was the inability to synchronize manpower and materiel, the two “basic commodities” of military mobilization as Marvin A. Kreidberg and Merton G. Henry describe in the History of Military Mobilization in the United States Army 1775–1945. In other words, the Army lacked a planning methodology for determining the type and quantity of materiel it needed and when.5

Stimulated by the chaotic mobilization in 1898 for the Spanish-American War, the Department of War developed rudimentary mobilization policies as a product of the Root reforms after the turn of the century. Compared to the sophistication and detail of later plans, these early efforts were the barest beginning. It was not until after World War I began that the Department of War under Secretary of War Lindley Miller Garrison examined the mobilization of personnel in any detail. The Army had never required mobilization plans since conscription had not figured centrally in the outcome of any American conflict, nor had the full weight of the nation’s economy ever been converted to wartime production. For example, as Kreidberg and Henry explain, America’s first draft during the Civil War yielded 6 percent of Union forces, while less than a third of the nation’s economic output accounted for war materials, compared to upward of 70 percent in World War II.6

World War I exhibited frightening new realities of industrial warfare, given the mass production of more sophisticated and more lethal weapons such as machine guns, tanks, airplanes, mobile high-caliber artillery, high-yield explosives, and chemical munitions. No longer could the Army rely on volunteers rallying to the flag to man its ranks or on limited segments of the economy to produce the increasingly complex war items at the scales required. Army leaders had to rethink their prewar preparations. Soon after the 1918 armistice was signed, the War Plans Division (WPD) of the general staff generated a rudimentary mobilization study. Planners collected data about manpower curves for either an offensive or a defensive war but neglected to provide information for materiel procurement.7

While the Army’s initial study focused on manpower mobilization, Congress laid the foundation for comprehensive mobilization planning by passing the National Defense Act of 1920. The act required the federal government to conduct studies and plan for industrial mobilization, handing responsibility to the assistant secretary of war. It also reorganized the Army into three components—Regular Army, National Guard, and Organized Reserve—which added useful measures to support any future use of the draft. Guard and reserve officers likewise gained responsibility on the general staff. Additionally, the Army divided the country into “corps areas” responsible for administering a “complete and immediate mobilization for the national defense in the event of a national emergency declared by Congress.” The law instituted the Army and Navy Munitions Board to develop mobilization timetables and wartime requirements, complementing the Joint Army and Navy Board established in 1903 for coordinating operational war plans. Finally, the act sharply reduced the Army’s funding but preserved end-strength by slimming down to 300,000—double the size of the prewar Army that many veteran officers found suitable for a peacetime force.8

Satisfaction with the sizable peacetime end-strength quickly soured as the public embraced isolationism and Congress questioned the need for a large standing army. Lawmakers slashed end-strength authorizations to 137,000 the following year. Facing headwinds that would endure for the next two decades—a skeleton force-in-being, a shoestring budget, and the swirling currents of isolationism—Pershing, chief of staff (1921–24) ordered the Army’s first mobilization plan around when the cuts took effect. Through the 1920s and into the 1930s, the general staff routinely revised its mobilization plans, though the early plans consistently failed to demonstrate the key connections between manpower and materiel. The main reason was that early plans were one dimensional, meaning they emphasized one commodity— either manpower or materiel—based on poor assumptions for the other.9

Creating an Ecosystem for Strategic Planning

Mobilization planning improved throughout the interwar period. As mentioned, the consistency of rewriting mobilization plans yielded benefits. The more officers tinkered on these matters as planners in the War Plans Division, the more experienced and seasoned planners the Army yielded. More importantly, the Army developed a strategic planning ecosystem beyond the general staff that consisted of four tenets as framed by Henry G. Gole. “The [Army] was resource poor in an isolationist country,” writes Gole in The Road to Rainbow: Army Planning for Global War, 1934–1940, “but it invested its limited resources and energy in education, training, studies, and planning.” These four tenets comprised an ecosystem that led to more concrete and comprehensive products. Officers drew connections between manpower and materiel while gaining awareness of mobilization’s inextricable links with arenas like public opinion, war plans, organizational design, military strategy and concepts, and national policy.10

The Army’s educational institutions laid the foundation for officers to consider mobilization issues throughout successive assignments rather than only when assigned as planners on the general staff. Rather than emphasize tactical lessons from student officers’ past experiences, curriculum enhanced strategic acumen through lectures, discussions, exercises, and other assignments. By considering matters such as coalition planning, theater strategy, force design, strategic support areas, and munitions procurement, officers gained an appreciation for the complexities of modern war that eclipse the battlefield. Following the National Defense Act of 1920, officers from the Guard and Reserve attended the US Army War College and the newly created Army Industrial College. The War Plans Division became the epicenter of strategic planning during this period, but the general staff leveraged the US Army War College as another planning arm. As Gole explores, student officers—many of whom later served in the War Plans Division as flag officers during World War II—gained training experience by war-gaming scenarios in coalition warfare based on the “color plans.” More to the point, Gole notes, Craig—chief of staff (1935–38) and former US Army War College commandant—added mobilization as a focal point in course curricula. Further, established in 1924, the Army Industrial College was intended “to develop logical thought in the problems involved in industrial mobilization,” according to a young Dwight D. Eisenhower, who graduated from the course and then spent two and a half years as a mobilization planner on the general staff.11

The Army produced several studies and plans throughout the interwar period examining issues such as industrial capacity, resource allocation, and manpower availability. One such plan was the Industrial Mobilization Plan (IMP). Mainly the result of Eisenhower’s efforts, the IMP of 1930—which identified the importance of government oversight, coordination with industry, and centralized control of wartime production—closed many recurring gaps in procurement planning and became the basis of all subsequent industrial mobilization plans until 1939. Additionally, the Army produced a plan series for procuring arms, munitions, and supplies known as the Procurement Plan. Yet, this plan and the Industrial Mobilization Plan lacked specificity regarding resources and were based on unrealistic assumptions about timelines and the availability of supplies.12

Despite these developments, the Army’s mobilization plans for materiel remained at odds with the war plans, that is the “color plans” like Japan (orange), Germany (blue), and Great Britain (red), because mobilization planning utilized the concept of defensive war while the war plans envisioned offensive operations overseas. Like the mobilization plans from this period, the color plans were more theoretical than concrete. Maurice Matloff, one of the authors of the Army’s official history of World War II, criticizes “the so-called ‘color plans’ . . . were little more than abstract academic exercises,” but they offered utility by revealing how the force-in-being was not capable of fulfilling potential wartime demands. The mismatch between mobilization plans and war plans can be attributed to the fact that they were planned independently and because the country’s isolationist mood nudged the Army to base mobilization planning on the concept of “passive defense.”13

Public sentiment was a key factor. A hypothetical offensive scenario found in the color plans was one thing, but concrete plans for embroiling a wary public in another foreign war would have been fraught with political risk. As Russell F. Weigley notes in The History of the United States Army, popular support for the military eroded following MacArthur’s, chief of staff (1930–35), controversial use of the Regular Army in 1932 to break up a group of veterans and their families, known as the Bonus Marchers, who demanded payment of their service certificates. Additionally, the late 1920s and early 1930s featured the height of antiwar literature, including A Farewell to Arms by Ernest Hemingway. Thus, influenced by public opinion coupled with a national policy of neutrality, the Army mobilization plans for organizing a wartime force were limited to modest requirements for hemispheric defense.14

Another planning series, the Protective Mobilization Plan (PMP), which first appeared in the mid-1930s, was based on the same defensive concept. Whereas the Industrial Mobilization Plan entailed matters of materiel, the Protective Mobilization Plan addressed manpower, namely conscription. Under the PMP, the National Guard would serve as the Army’s primary reserve force in wartime, but slender appropriations prohibited sizable investment into their training. Instead, the PMP exemplified the Army’s reliance on mobilizing the “citizen soldier” to supplement the force on paper, given that the Regular Army, National Guard, and Organized Reserve could not achieve the perceived wartime goals. It further showcased considerations like timing and synchronization, as ordnance planning documents reveal, by computing ammunition requirements based on troop training schedules. Strict measures like universal military training never materialized, as key figures like Pershing and Marshall had hoped, but the Army benefited from other training programs that prepared single men for military service. For example, the Civilian Conservation Corps, or “Tree Army,” employed more than three million men in civil works projects under military-like conditions.15

Plans during this period needed to account for “the emergence of combined operations,” a trend of mid-twentieth-century warfare observed by Larry H. Addington, which “increasingly erased the dividing lines among land, sea, and air forces . . . [so] interservice doctrine and leadership became crucial to success.” The joint boards formalized cooperative planning between the Army (including its ground and air forces) and the Navy. With war planning, for example, the Army had to factor in how many ground service troops were required to enable tactical air operations, while the sea services had to consider the number of troop transports and support vessels for amphibious campaigns. Similarly, the military departments had to cooperate in mobilization planning, considering the Army and the Navy (and industry) drew from the same resource pools for manpower, raw materials, and production capacity. The demands for the sea service’s ship-building program were sizable. By incorporating insights from civilians like financier Bernard Baruch, who remedied the nation’s economic mobilization during World War I, mobilization planners in the 1930s accepted a realistic assumption of civilian oversight. However, the Department of War fell short of organizing a centralized planning agency that would allow planners to produce a single comprehensive plan.16

While the Army’s mobilization plans for most of the interwar period were not well matched for the turbulent years ahead, the budding ecosystem for strategic planning yielded several benefits. By the late 1930s, plans reflected the imperative to begin mobilization operations well in advance, scrapping the false assumption found in early plans that supplies would simply arrive when needed. The Army leveraged its educational institutions as other planning arms and, as Gole highlights, gained “a nucleus of professional officers schooled in analytical thinking . . . keenly aware of the political component of strategic planning.” For example, an Industrial College directive from the 1939–40 course prompted student officers to test the validity of the PMP by computing supply requirements based on a predetermined troop basis. Evolutions of the Industrial Mobilization Plan and Protective Mobilization Plan likewise demonstrated how planners came to grasp sequencing and timing in mobilization operations. Yet, several shortcomings remained, such as the daylight between the assumptions driving mobilization plans and those driving war plans, plus the Army’s limited collaboration with industry. These issues became more acute as the global security environment sharply deteriorated by the end of the decade.17

Interrelationships in Mobilization Planning

Germany altered the global security landscape overnight by invading Poland on September 1, 1939, the same day Marshall became the Chief of Staff of the Army. Japan, meanwhile, was extending its military adventurism in Asia, having invaded China two years before and Manchuria in 1931. Weeks later, Germany, Japan, and Italy signed the Tripartite Pact, establishing the Axis powers alliance. At this juncture, Marshall recognized the Army’s peacetime plans were inadequate. He scrapped the abstract color plans and commissioned the first set of concrete war plans to envision a global conflict known as the “rainbow plans.” While Congress had steadily increased the Army’s appropriations beginning in the mid-1930s, a softening stance on US neutrality meant rearmament had become Marshall’s and, thus, the Army’s most urgent matter.18

Shortly following the outbreak of war in Europe, President Franklin D. Roosevelt announced a “cash and carry” policy that relaxed America’s official stance on neutrality by providing materiel to Great Britain and France. A year later, Congress narrowly passed the only peacetime draft in US history, providing fresh means for expanding the Army’s ranks, albeit temporarily, given the draftees carried limited enlistment periods. Materiel shortages persisted despite the swelling size of the force, echoing challenges from the World War I era mobilization experience. Faced with the skyrocketing demand for war items at home and abroad, the president hand-picked economists and industrialists to scale production and shift the economy toward a war footing. In early 1941, Congress passed the Lend-Lease Act, accelerating overseas commitments of US-manufactured materiel, which now included the Soviet Union and China and flooded the military establishment with appropriations nearly topping $1 billion, a tenfold increase from two decades before.19

Despite the production increases and growing troop numbers, it was clear the Spartan-sized, defensive oriented, and poorly equipped Army of the interwar years lacked a suitable guidepost for marshaling a large wartime force capable of conducting offensive operations on multiple fronts overseas. The president thus discarded the PMP and IMP because they “proposed logistical solutions that had already been ignored in the almost two years of mobilization,” writes Edward M. Coffman. Furthermore, it was unclear to what end and for how long the United States would muster its human capital and materiel resources. Official policy on neutrality notwithstanding, the Army required a more comprehensive set of mobilization plans to generate a force likely to dwarf the current force even after marshaling the National Guard and Organized Reserve. There was a growing likelihood that the United States would soon be fighting as part of a coalition in a global war, so it was important for the Army to anticipate future policy developments and plan accordingly. Army leaders took the first step by linking war plans with mobilization plans for the first time.20

In April 1941, Under Secretary of War Robert Patterson called for a study to determine the resources required to defeat the Axis powers—a clear shift from basing requirements on “passive defense.” Marshall subsequently tasked the WPD, headed by Brigadier General Leonard T. Gerow, to prepare “a more clearcut strategic estimate of our situation from a ground, air, and naval viewpoint.” Marshall surmised an initial mobilization paper from the Army would “provide a base of departure . . . [that] could be utilized as the basis for obtaining the views of other departments.” For instance, Navy officials felt they could not determine fleet requirements for a global conflict unless the nation was at war.21

Marshall then tapped Major (later General) Albert Wedemeyer to develop a new collaborative planning framework later known as the Victory Program, or Victory Plan. According to Charles E. Kirkpatrick, Wedemeyer and his cohort produced “a comprehensive statement of American strategy that served as a fundamental planning document in preparing the country for war.” Kirkpatrick claims the Victory Program departed from the traditional question “What can the Army accomplish with the force at its disposal?” Rather, asking, “What sort of force does the Army need to accomplish the national strategy?” The problem, however, was that there was no national strategy—only an ambiguous policy on neutrality.22

A historical debate illuminates how mobilization planning transcends the Army. In his book, Keep from All Thoughtful Men: How U.S. Economists Won World War II, Jim Lacey challenges Kirkpatrick’s conclusion that the Victory Program yielded a fundamental planning document that prepared the nation for war. He claims the “real Victory Program” resulted from two documents completed before Wedemeyer undertook his assignment. First was the US Navy’s Plan Dog memorandum of November 1940 that initially outlined the “Europe-first” policy. Second was the Anglo-American Consolidated Statement, which “formulated by the now almost forgotten [economist] Stacey May, that determined what materials were available for the build-up of Anglo-American military forces.”23

Debate aside, industry could not answer the key question of how the Army would fight. Only the military establishment could determine its requirements based on several interrelated factors, yet the military had been providing little more than vague figures to industry leaders like William S. (Bill) Knudsen whom the president tapped to lead the newly formed Office of Production Management (OPM). “That’s not what I want,” Knudsen groaned when reviewing the military’s so-called requirements, “I want to know what kind of equipment you need for these men—and how many pieces of each kind. Please tell me how many pieces.”24

As the head of OPM, Knudsen may have appreciated the personnel demands of raising an Army, given his years of experience working with labor unions in the automobile industry, “But I know if we get into a war,” Knudsen said, “the winning of it will be purely a question of material and production.” Knudsen’s comment dismisses battle outcomes and downplays the association between manpower and materiel, but his sentiment is well placed. The OPM and other newly instituted civilian agencies and bureaus had to coordinate contracts, balance time schedules, and resource projects for military departments competing over the same labor pools, stockpiles of raw materials, and assembly plants. In short, industry leaders could not organize their tasks unless the military estimated what it needed to fight and win a global war.25

Determining the Ultimate Requirements

Nazi Germany’s surprise invasion of the Soviet Union in June 1941 encouraged the president, known for temporizing policy decisions, to ascertain the “ultimate requirements” for war. Fortunately, Department of War officials had anticipated these developments. “I realize that this report involves the making of appropriate assumptions as to our probable friends and enemies,” Roosevelt confessed, “and to the conceivable theaters of operation which will be required.” Gerow and his War Plans Division planners had to intuit which direction policy would take, namely by drawing upon Rainbow 5, which assumed the United States, allied with Great Britain and France, would build up forces in Europe for a transatlantic offensive against Germany while maintaining a defensive posture in the Pacific against Japan.26

In the final months before Pearl Harbor, Marshall confronted the reality that the enlistments of peacetime draftees would expire. Many enlistees had recently completed complex, large-scale training exercises such as the Louisiana Maneuvers, so the Army stood to lose much of its recently gained experience. Additionally, Marshall fretted over shortfalls in equipping his force, considering a large swath of American-manufactured war items were being shipped overseas. In essence, ambiguous rearmament goals and uncoordinated commitments to warring nations complicated the Army’s ability to determine a comprehensive set of requirements.27

The Victory Program’s combined arms approach to force design placed a premium on airpower, mobility, and mechanized forces with armor coupled with the need to assemble, equip, transport, and sustain millions of expeditionary forces dispersed throughout multiple theaters. “We must first evolve a strategic concept of how to defeat our potential enemies and then determine the major military units (Air, Navy, Ground) required to carry out the strategic operations,” Wedemeyer suggested. He then estimated 10 percent of the male population could be drafted into the military without damaging the national economy based on previous studies. By comparison, the Soviet Union nearly toppled its economy in 1942 by mobilizing 35 percent of the male population. The War Plans Division produced a troop basis of 8,795,658—a remarkably accurate estimate (or a lucky guess as Lacey suggests) compared to the actual number of 8,291,336 at the Army’s peak size in May 1945.28

The force composition aspects for ground elements, however, were off the mark. The WPD planners designed a force to defeat Germany based on the presumed Europe first policy but overestimated the need for armored and motorized divisions. Wedemeyer later admitted his failure to account for the Army’s logistical requirements in the Asia/Pacific theater. In a twist demonstrating another aspect of the interrelationship between mobilization plans and public opinion, the Victory Program was leaked days before Pearl Harbor, creating a public relations nightmare for the president and for the Department of War. Despite the flub, Wedemeyer summarized his experience as being “intimately involved in an attempt to see the war whole . . . adapting Grand Strategy to a conflict of global dimensions.”29

“The success of the Victory Plan therefore drove home a point long ignored in American military planning,” Kirkpatrick summarizes. “It reminded the War Department that mobilization and operations are not distinct entities, but parts of a single coherent plan.” Wedemeyer was hardly alone (despite how much credit the Army’s official history proffers him) and may have been less influential based on the evidence Lacey presents. For instance, Colonel Henry Aurand, the Army’s acting assistant chief of staff, G-4, produced an estimate of munitions as part of a combined study completed in June 1941 before Wedemeyer submitted his final report in September. The collaborative planning that occurred among a multidisciplined community of interest began connecting the intertwined elements of manpower and materiel mobilization and their association with war plans. Revised force designs, integrated war plans, modified production goals, detailed procurement schedules, and even the composition of local draft boards—issues that transcended the Army—matured from the process to determine a comprehensive set of mobilization requirements.30

Evolving Army Transformation

Today, protracted fighting among warring states offers real-time insight into the effectiveness of large-scale mobilization planning. Fresh analysis such as A Call to Action: Lessons from Ukraine for the Future Force identify challenges that bear resemblance to the interwar period, particularly Stephen K. Trynosky’s insights on strategic depth and manpower reserves. But the Army’s so-called continuous transformation has thus far applied lessons emphasizing the tactical war fighting realm. These include the dominance of fires and autonomous systems, advanced technologies like loitering munitions and artificial intelligence, and challenges associated with massing, maneuvering, and front-line logistics. While these efforts are important, the Army’s transformation initiatives have yet to embrace pressing strategic challenges like the complexities of mobilizing entire populations and economies quickly, at scale, and for prolonged periods—and synchronizing the countless activities to deliver a force on time and at the required locations, suited to the environments, designed to defeat multiple threats but with one clearly prioritized, while accounting for intangibles like societal resilience and will to fight.

Present circumstances differ from the interwar period in some ways. Unlike after World War I, the contemporary force would not have to develop a new planning methodology from scratch. Existing systems and processes are optimized for steady-state operations, but they can be modified rather than scrapped. Further, the roles and responsibilities of the former Department of War are not the same as the post–Goldwater-Nichols Department of Defense (including the prominent role of the National Guard Bureau in mobilization affairs according to law), but mobilizing remains a core function of the Department of the Army.31

Further, prewar planners did not contend with a sluggish acquisition system along with the powerful influence of the military-industrial complex, a by-product of World War II mobilization. Today’s all-volunteer force dwarfs the composition from the interwar years in terms of capability and capacity, which is desirable, but a robust force-in-being inhibits the urgency to plan for immense wartime expansion surpassing Guard and Reserve augmentation. The silver lining regarding recent murmurs over troop cuts upward of 90,000 may heighten the urgency for the Army to prioritize its prewar strategic planning requirements in addition to the ongoing tactical upgrades.32

Considering how much has atrophied since the Army last prioritized large-scale mobilization planning nearly four decades ago, a recent think tank report titled “Back to the Drafting Board” sounds the alarm on the America’s inability to enact a draft, should the need arise. The report suggests the Selective Service System is in disorder, mobilization processes and systems are outdated, and the infrastructure to support large-scale mobilization does not exist. Further, as Trynosky identifies, the available pool of replacement manpower is smaller today than before the peacetime draft was enacted in 1940. Finally, technologies have evolved dramatically, and their impacts are evident on the battlefields of today’s hot wars. Digital Age technologies, like artificial intelligence and quantum computing, will play major roles in future large-scale mobilization operations, especially when considering Industrial Age scales.33

More important, however, are the similarities such as the shared reality that the force-in-being in both eras despite their difference in size could not and cannot, respectively, meet the demands of a large-scale, protracted war. Secretary of the Army Dan Driscoll admitted so in his first message to the force. Commitments for US-manufactured war items run high in both cases, given the parallels between Lend-Lease and sizable military aid packages for Ukraine and other contemporary actors. Moreover, the rainbow plans and the current war plans, according to the Joint Strategic Planning System, share an assumption of simultaneity, or the likelihood of war on multiple fronts. In other words, planning guidance suggests the growing potential for global war despite clear benefits and a desire for designing a force to win a short, sharp war. Like the interwar period, no equivalent mobilization plans exist for these potentially catastrophic scenarios. In fact, the Department of Defense’s last Master Mobilization Plan was inked by the Reagan administration. Considering these similarities, the body of thought from the interwar years should influence how the Army prepares for large-scale wars of the future, namely how senior leaders approach the Army transformation initiative. Preparing to marshal the nation’s manpower and materiel resources for war has once again become the Army’s most pressing matter.34

In fairness, the Army has upscaled rehearsals of mobilization operations at key installations and incorporated new technologies to speed up the mobilization of US Army Reserve units. Army leaders have also made strides with defense industries to upscale production of critical munitions and key ground systems. Yet, the Army requires significant changes to carry out large-scale mobilization operations in ways that may amount to an institutional overhaul. For instance, overcoming the challenges associated with replacements and reconstitution—based on a sobering but realistic assumption of thousands of casualties per day, according to Army doctrine, in large scale combat—may require major changes in training, equipping, recruiting, force structure, organizational design, facilities construction and maintenance, regulations, and doctrine. Similarly, the demands of large-scale deployment operations—as fresh mobilization plans will likely reveal—may require additional protection measures and transportation infrastructure, to include domestic rail, airlift, and sealift.35

A new set of mobilization plans featuring a comprehensive strategic estimate of requirements would reveal the magnitude of the problem, far surpassing Guard and Reserve mobilization. Rapidly instituting a draft, given current shortfalls with the Selective Service System, or scaling industrial production of basic and high-tech war items five, ten, or twentyfold overnight is impossible. Instituting a new strategic planning process now, however, will spark the necessary collaboration on these critical matters with other parts of the military enterprise—to include the Office of the Secretary of Defense, the Joint Staff, the other military departments, and the National Guard Bureau—along with other government agencies and industry leaders. For instance, as Lacey highlights, economists, financiers, and industry leaders perform outsized roles in mobilization planning, but most of that expertise resides beyond the Army’s ranks.36

Military bureaucracy is more complex today than before World War II, but a dedicated process will similarly steer the Army toward a modern-day ecosystem for strategic planning by leveraging low-cost investments in education, studies, and training. Creating a centralized mobilization planning effort will instill an edge for transitioning to large-scale war over the important-but-narrower outlook of modernizing the force. For instance, it is imperative the Army approach force design by considering where and how to employ a large cadre of qualified and experienced officers, noncommissioned officers, and specialized soldiers to grow the force in time of need. Materiel issues beyond the Army’s purview, such as complex assembly processes, supply chain vulnerabilities, manufacturing limitations, and raw material shortages, will thwart the ability to scale production rapidly unless they are addressed beforehand. Finally, restoring capacity to enact a draft or shift to an economic war footing quickly—actions requiring Army oversight and resources to implement—may prove determinative from a deterrence perspective, forestalling the calamity of great-power war.37

Applying Lessons

While observations from ongoing conflicts may stimulate a grassroots renewal of mobilization planning for large-scale war, it is important Army senior leaders direct action now by adding mobilization as a transformation focus area. The Army’s historical experience can serve as a blueprint. The first step should be to commission a new set of mobilization plans, given the growing likelihood of a protracted large-scale war involving the United States. Army leaders should then design and institute a modern strategic planning ecosystem through education, studies, training, and planning. Finally, Army leaders should incorporate large-scale mobilization as a core component of executive decision making, given how these matters impact areas inside and outside their purview.

An emphasis on mobilization from leadership should not come as a surprise either internally or externally but rather as a necessary evolution of the Army’s continuous transformation for large-scale war. For instance, the Department of Defense has tasked the military departments to develop new plans for integrating upward of one million inductees into the military. This comes on the heels of the first-ever National Defense Industrial Strategy, which highlights steps to address vulnerabilities associated with economic mobilization. Importantly, the National Defense Industrial Strategy identifies links, opportunities, and vulnerabilities associated with mobilization—such as military readiness, supply-chain resilience, workforce development, defense innovation, strategic autonomy, government collaboration, and prioritization. Although reintroducing mobilization designs will likely stir controversy and possibly create “political dynamite,” as Wedemeyer once jibed, the risks of inaction and failing to deliver a wartime force dwarf any potential fallout stemming from unpopularity.38

While the Army’s early efforts in mobilization planning after World War I generated products of limited utility, the process proved invaluable by addressing challenges of extraordinary magnitude. Throughout the interwar years, planners improved the quality of their products because of a steady planning cadence enhanced by an ecosystem for strategic planning. Mobilization plans thus came to reflect the connections between manpower and materiel and began to account for the links with arenas like public opinion, war plans, and national policy. On the eve of war, the Army was thinking big—with eye-watering, but realistic strategic estimates—by thoughtfully tailoring its requirements based upon a presumed offensive wartime policy, expected operational environments, interdependencies of joint warfare, on top of the strategic demands for rapidly assembling, deploying, and sustaining a colossal wartime force.39

“The Army used to have all the time in the world and no money,” Marshall remarked after Pearl Harbor, “now we’ve got all the money and no time.” Although it lacked the means at the outset, the Army was more ready for the demands of large-scale war than any other period in its history. Synthesizing the multidimensional aspects of military readiness therefore flowed from the process to determine the “ultimate requirements” for victory. The Army must overcome the complexities of planning for large-scale war by rediscovering how mobilization defines the risk and drives decisions in areas like force development and in other areas that transcend the Army’s core functions. The Army’s historical experience demonstrates that effective mobilization planning is crucial for generating and sustaining a large wartime force. By restoring the primacy of mobilization planning, the Army will upgrade how it transforms to fight and win potential large-scale wars of the future.40

 
 

Tim Devine
Lieutenant Colonel Tim Devine is a US Army strategist and instructor at the US Army Command and General Staff College. He recently completed a multiyear assignment in the Indo-Pacific and previously served in the historic US Army War Plans Division analyzing mobilization and deployment issues at the Pentagon. He is a fellow in the Lieutenant General (Retired) James M. Dubik Writing Fellows Program and a former AH-64D Apache aviator.

 
 

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Endnotes

  1. James E. Rainey, “Continuous Transformation: Transformation in Contact,” Military Review, August 2024, https://www.armyupress.army.mil/Journals/Military-Review/Online-Exclusive/2024-OLE/Transformation-in-Contact/; Jane Harman et al., Commission on the National Defense Strategy” (RAND, July 2024), ix. See also Stephen K. Trynosky, “Paper TigIRR: The Army’s Diminished Strategic Personnel Reserve in an Era of Great Power Competition” (research project, US Army War College, 2023); John A. Nagl and Katie Crombe, A Call to Action: Lessons from Ukraine for the Future Force (US Army War College Press, 2024), https://press.armywarcollege.edu/monographs/968/; “The Army’s Vision and Strategy,” United States Army, n.d., accessed February 27, 2025, http://www.army.mil/about/; and Dan Driscoll and Randy A. George, “Letter to the Force: Army Transformation Initiative,” U.S. Army, May 1, 2025, https://www.army.mil/article/285100/letter_to_the_force_army_transformation_initiative. Return to text.
  2. Marvin A. Kreidberg and Merton G. Henry, History of Military Mobilization in the United States Army 1775–1945, Headquarters, Department of the Army (HQDA) Pamphlet 20-212 (HQDA, 1955), 221–29, https://apps.dtic.mil/sti/trecms/pdf/AD1133414.pdf; and Jean Lopez et al., World War II Infographics (Thames & Hudson, 2019), 28–29. Return to text.
  3. Colonel Harold W. Nelson, “Foreword to Charles E. Kirkpatrick,” in An Unknown Future and a Doubtful Present: Writing the Victory Plan of 1941, Historical Analysis Series, Center of Military History (CMH) Pub 93-10 (CMH, 1990), v. Return to text.
  4. Kreidberg and Henry, Military Mobilization, 438; David L. Roll, George Marshall: Defender of the Republic (Dutton Caliber, 2019), 61; and Frank N. Schubert, Mobilization: The US Army in World War II – The 50th Anniversary, CMH Pub. 72–32 (CMH, 1995), 4, https://archive.org/details/Mobilization. Return to text.
  5. Arthur Herman, Freedom’s Forge: How American Business Produced Victory in World War II (Random House Trade Paperbacks, 2013), 13; and Kreidberg and Henry, Military Mobilization, 221–29. Return to text.
  6. Kreidberg and Henry, Military Mobilization, 108, 183. Congress rejected the War Department’s plan for a federal reserve known as the “Continental Army” in favor of a less radical alternative to reorganize the National Guard that became law with the National Defense Act of 1916. Even then, the General Staff and Congress were solely concerned with people and largely ignored the issue of materiel. Additionally, the episode showcases a recurring theme in US Army’s history regarding oscillating support for a large standing force versus a proclivity for militia forces and volunteers. See “Federalizing the National Guard: Preparedness, Reserve Forces and the National Defense Act of 1916,” National Guard Bureau Historical Services, June 2, 2016, https://www.nationalguard.mil/News/News-Features/Article/789220/federalizing-the-national-guard-preparedness-reserve-forces-and-the-national-de/; and Lopez et al., Infographics, 179. Return to text.
  7. Kreidberg and Henry, Military Mobilization, 4; and Acting Director, War Plans Division, to Chief of Staff, memorandum, “Manpower Curves,” November 14, 2019, in Kreidberg and Henry, Military Mobilization, 382. Return to text.
  8. An Act to amend an Act entitled “An Act Making Further and More Effectual Provision for the National Defense, and for Other Purposes,” H. Doc. 65-215 (1916); To Establish Military Justice, 66th Cong., Pub. L. No. 66–242, § 227, 759 (1920), 764–65; Edward M. Coffman, The Regulars: The American Army 1898–1941 (The Belknap Press of Harvard University Press, 2004), 231; and Russell Weigley, History of the United States Army (Indiana University Press, 1969), 401. Return to text.
  9. Colonel J. L. DeWitt, War Plans Division, to Colonel B. H. Wells, War Plans Division, September 7, 1921, memorandum, “Plan for Operation Involving the Maximum Effort” in Kreidberg and Henry, Military Mobilization, 389. Return to text.
  10. Henry G. Gole, The Road to Rainbow: Army Planning for Global War, 1934–1940 (Naval Institute Press, 2003), xvii. Return to text.
  11. Also see Maurice Matloff and Edwin M. Snell, Strategic Planning for Coalition Warfare, 1941–1942, United States Army in World War II, CMH Pub 1-3 (CMH, 1953); Gole, Road to Rainbow, 156; and Dwight D. Eisenhower in Coffman, The Regulars, 284. Return to text.
  12. Kerry E. Irish, “Apt Pupil: Dwight Eisenhower and the 1930 Industrial Mobilization Plan,” The Journal of Military History 70, no. 1 (January 2006): 3, https://digitalcommons.georgefox.edu/hist_fac/27/. Return to text.
  13. Maurice Matloff, “Prewar Military Plans and Preparations, 1939-1941,” Proceedings 79, no. 7 (July 1953): 87, 88, https://www.usni.org/magazines/proceedings/1953/july/prewar-military-plans-and-preparations-1939-1941. Return to text.
  14. Weigley, United States Army, 402; and Stetson Conn and Byron Fairchild, The Western Hemisphere: The Framework of Hemispheric Defense, United States Army in World War II, CMH Pub 4-1 (CMH, 1960), 96–97. Return to text.
  15. “Requirements Protective Mobilization Plan and Augmentation Plans,” Procurement Plans Division, Planning Branch, October 24, 1939, in Charles Loucks papers, box 22, folder 1, US Army Heritage and Education Center; and “Civilian Conservation Corps,” National Park Service, n.d., accessed January 27, 2025, https://www.nps.gov/thro/learn/historyculture/civilian-conservation-corps.htm. Return to text.
  16. Larry H. Addington, The Patterns of War Since the Eighteenth Century, 2nd ed. (Indiana University Press, 1994), 264; and Kreidberg and Henry, Mobilization, 14. Return to text.
  17. Kreidberg and Henry, Mobilization, 8; Gole, Road to Rainbow, xvi; and “Problem No. 17 – Directive: Procurement Requirements of the Protective Mobilization Plan and Augmentation Plan – 1939” (US Army Industrial College, Course 1939–40) in Charles Loucks Papers, box 22, folder 1, US Army Heritage and Education Center. Return to text.
  18. Kirkpatrick, Unknown Future, 33. Return to text.
  19. The Selective Training and Service Act of 1940, also known as the Burke-Wadsworth Act, was signed into law on September 16, 1940. See Paul Dickson, Rise of the G.I. Army 1940–1941 (Grove Atlantic, 2020), 86–87; and Elias Huzar, “Military Appropriations, 1933–1942,” Military Affairs 7, no. 3 (Autumn 1943): 144, https://doi.org/10.2307/1982883. Return to text.
  20. Coffman, The Regulars, 377. Return to text.
  21. Undersecretary of War for Secretary of War, memorandum, “Ultimate Munitions Production Essential to the Safety of America,” April 18, 1941, in Mark Skinner Watson, Chief of Staff: Pre-War Plans and Preparations, United States Army in World War II, CMH Pub 1-1 (CMH, 1991), 87–88, https://history.army.mil/Portals/143/Images/Publications/Publication%20By%20Title%20Images/C%20Pdf/CMH_Pub_1-1.pdf?ver=yW3C10tfWWbPvqAXYKAfYw%3d%3d; Chief of Staff files, “Notes on Conference,” May 1941, and unused Chief of Staff for Undersecretary of War, memorandum, “Stepping up Orders,” in Watson, Chief of Staff, 335–36; and Jim Lacey, Keep from All Thoughtful Men (Naval Institute Press, 2011), 68. Return to text.
  22. Kirkpatrick, Unknown Future, 119, 122. Return to text.
  23. Lacey, Keep, 31. Return to text.
  24. Interview with Major General James H. Burns, summer 1950, and notes from William Knudsen and Leon Henderson in Civilian Production Administration (CPA), Minutes of the Advisory Commission to the Council of National Defense (CPA: 1946), 12; and Harry C. Thompson and Lida Mayo, The Ordnance Department: Procurement and Supply, United States Army in World War II, CMH Pub 10-10 (CMH, 1960), 45–46. Return to text.
  25. Bill Knudsen left the Office of Production Management (OPM) in January 1942 the same day OPM was disestablished and replaced with the War Production Board (WPB) over personality conflicts. Roosevelt softened Knudsen’s departure by appointing him as the War Department’s Director of Production, where Knudsen earned the distinction as the only civilian in the Army’s history to be appointed to the rank of lieutenant general. See Herman, Freedom’s Forge, 83 and Lacey, Keep, 70. Return to text.
  26. Acting Chief of Staff War Plans Division for Assistant Chief of Staff G-4, memorandum, “Ultimate Requirements for the Army, WPD 4494-4 and G-4/33473” August 23, 1941, in Watson, Chief of Staff, 347; President Franklin D. Roosevelt to Secretary of War Henry Stimson and Secretary of the Navy Frank Knox, July 9, 1941, in Watson, Chief of Staff, 338–39; and Matloff, “Prewar,” 341. Return to text.
  27. Congress voted to extend the Selective Service Act of 1940 on August 18, 1941, passing the House by the thinnest margin of a single vote. Roll captures the drama of events, including the importance of Marshall’s lobbying efforts, in George Marshall. See also Richard J. Overy, Why the Allies Won (W. W. Norton, 1997), 191. Return to text.
  28. Albert C. Wedemeyer, Wedemeyer Reports! (Henry Holt and Company, 1958), 66; Wedemeyer, Reports!, 73–74; Lopez et al., Infographics, 22–23; and Kreidberg and Henry, Military Mobilization, 623. Return to text.
  29. Thompson and Mayo, Ordnance Department, 59; Wedemeyer, Reports!, ix, 75. The tooth-to-tail ratio (that is, combat forces compared to support forces) was 1:2 in Europe, but the ratio was widely lopsided in the Asia/Pacific theater at 1:18. This imbalance was due to differences in the maritime nature of operations, vast distances, and noncontiguous geography of the latter’s theater. See also Overy, Allies Won, 319; and Chesley Manly, “F. D. R.’s War Plans!” Chicago Tribune, December 4, 1941. Return to text.
  30. Kirkpatrick, Unknown Future, 116. See Henry S. Aurand, Papers 1873–1978 (Dwight D. Eisenhower Library), https://www.eisenhowerlibrary.gov/sites/default/files/finding-aids/pdf/aurand-henry-papers.pdf; and “The Determination of Army Supply Requirements” in Lacey, Keep, 14. Return to text.
  31. More specifically, 10 US Code § 7013 – “Secretary of the Army” lists the functions of the Department of the Army to include (7) Mobilizing and (8) Demobilizing, https://www.law.cornell.edu/uscode/text/10/7013. Return to text.
  32. Steve Beynon, “Army Planners Are Weighing Force Reductions of Up to 90,000 Active-Duty Soldiers,” Military.com, April 3, 2025, https://www.military.com/daily-news/2025/04/03/army-mulling-dramatic-reduction-of-tens-of-thousands-of-troops.html. Return to text.
  33. Katherine L. Kuzminski and Taren Dillon Sylvester, “Back to the Drafting Board: U.S. Draft Mobilization Capability for Modern Operational Requirements,” Center for New American Security, June 18, 2024; and Stephen K. Trynosky, “Paper TigIRR,” 167. Return to text.
  34. Dan Driscoll, “26th Secretary of the Army: My Share of the Task,” U.S. Army, February 28, 2025, https://www.army.mil/article/283429/26th_secretary_of_the_army_my_share_of_the_task; “Joint Strategic Planning System,” Joint Staff (JS) (JS, January 29, 2024), D-2, https://www.jcs.mil/Portals/36/Documents/Library/Instructions/CJCSI%203100.01F.pdf; and P. Edwards, Master Mobilization Plan (Office of the Assistant Secretary of Defense [OASD], May 1988), https://apps.dtic.mil/sti/pdfs/ADA267855.pdf. Return to text.
  35. Robert Cope et al., “Modernization in Army Mobilization,” U.S. Army, September 1, 2021, https://www.army.mil/article/249904/modernization_in_army_mobilization; and HQDA, Sustainment Operations, Field Manual (FM) 4-0 (HQDA, July 2019), 4-4. Return to text.
  36. Lacey, Keep, 2–7. Return to text.
  37. Kuzminski and Sylvester, “Drafting Board,” 6. Return to text.
  38. Kathleen Hicks, memorandum, “Assignment of Executive Agent for National Mobilization,” August 2, 2024; Department of Defense (DoD), National Defense Industrial Strategy (DoD, 2023) 7–9, https://www.businessdefense.gov/docs/ndis/2023-NDIS.pdf; and Wedemeyer, Reports!, 36. Return to text.
  39. For more on how the Army organized its higher echelons for implementing large-scale mobilization operations, see Jim Dan Hill et al., The Organization of Ground Combat Troops, vol. 53, United States Army in World War II, CMH Pub 2-1 (CMH, 1948). Return to text.
  40. George C. Marshall in Kirkpatrick, Unknown Future, 35; and Weigley, United States Army, 436. Major Wedemeyer prepared three separate reports on the “ultimate requirements” for Army, ground, and air forces that Secretary of War Stimson delivered to the White House on September 25, 1941 accompanied by a single Joint Board report and a letter cosigned by the Secretary of War and Secretary of Navy. See also Matloff, “Prewar,” 351. Return to text.