Key Points

• Mobilization readiness is the nation’s ability to convert resources into military power at speed and scale.
• Unlike operational mobilization, which deploys and sustains existing forces, strategic mobilization expands military power by surging spending, personnel, and weapons production.
• It rests on four foundations: economic strength, workforce capacity, industrial capacity, and political will. Because any one of these can become the bottleneck, it must be assessed through multiple indicators, not a single score.
• In protracted war, the key question is not just who starts stronger, but who can mobilize faster, replace losses more rapidly, scale up production more effectively, and sustain high-intensity operations longer.

Executive Summary

Recent wars have exposed a reality that peacetime defense planning often understates: Stockpiles are finite, production does not surge overnight, and success in a protracted conflict depends as much on the ability to regenerate combat power as on the ability to win early battles. This report argues that mobilization readiness—the nation’s ability to convert resources into military power at speed and scale—is a central but underappreciated dimension of military readiness. Mobilization readiness rests on four foundations: economic strength, workforce capacity, industrial capacity, and political will. The United States retains major advantages in each of these areas, but it also faces serious constraints, including mounting fiscal and debt pressures, limited industrial depth, accelerating technological complexity, and a fractured political environment. The core policy question is no longer whether mobilization matters, but whether the United States can mobilize credibly and at sufficient speed and scale to deter and, if necessary, prevail in a large-scale, protracted war.

Introduction

Recent experience in large-scale attrition warfare from Ukraine to the Middle East has refocused attention in national defense on what peacetime planning tends to gloss over.¹ Stockpiles are finite, surge capacity is not instantaneous, the pace of innovation and adaptation is increasingly important, and the ability to scale matériel production and the size of military forces often matters as much as the ability to win early battles. The 2026 National Defense Strategy, for example, calls for “nothing short of a national mobilization . . . on par with similar revivals of the last century that ultimately powered our nation to victory in the world wars and the Cold War that followed.”² While previous strategies focused more on the readiness of the forces at hand—their ability to fight tonight (operational readiness), their technological edge (modernization readiness), and the size and composition of forces (structural readiness)— this new strategy evokes a fourth type of readiness that has too often been overlooked in the post–World War II era.³

Mobilization readiness is a nation’s ability to convert its resources into military power. It sets the upper bounds on how fast the military can grow, how large it can become, and how long it can sustain high-intensity conflict. It is “the readiness to get ready.”⁴ The Defense Department’s strategic readiness framework includes a mobilization dimension that focuses on increasing the capacity and availability of personnel, industry, and matériel.⁵ However, unlike operational, structural, and modernization readiness—which are largely determined within the military itself—mobilization readiness depends more broadly on a nation’s economy, workforce, industry, and political will.

The type of mobilization discussed in the strategy is not the military’s ability to activate, deploy, and sustain forces in contingency operations—what is better described as operational mobilization (a key component of operational readiness). Mobilization readiness, as used here, is concerned with strategic mobilization: the ability to rapidly increase defense spending, personnel, and weapons production. Whereas operational mobilization opens the pipelines of military power that already exist and keeps them flowing, strategic mobilization widens those pipelines and creates entirely new conduits of military power.

Importantly, mobilization readiness does not merely support growing the military—this type of readiness also shapes how the military grows through what types of forces can be built and how quickly they can be fielded. Strategic mobilization is a competitive process in which each side seeks to not only expand its own production and sustainment capacity but also disrupt, degrade, or outpace that of its adversary. Mobilization is inherently relative and shaped by the interaction of opposing systems.⁶

This report explores what strategic mobilization requires in the modern era and identifies key indicators of mobilization readiness. It begins with the US tradition of strategic mobilization and the lessons learned from prior wars. It then assesses the economic, workforce, industrial, and political drivers that govern mobilization readiness and proposes practical indicators for each. It concludes by considering a question of growing importance: What would a strategic mobilization look like today?

The Forgotten Tradition

For the first 175 years of its history, the US military followed a predictable pattern when transitioning from war to peace. After each major conflict, from the Revolutionary War until the Korean War, the United States consistently and thoroughly demobilized its military. Mobilization readiness became essential to the new republic—not by deliberate strategy, but by self-induced necessity. The military had to rebuild from a minimal peacetime force posture whenever conflict arose, which meant that structural, operational, and modernization readiness received relatively little attention in peacetime. Yet although the military relied heavily on mobilization readiness, it often found its ability to mobilize lacking and uneven.

The depth of demobilization in the early years of the US military is surprising in hindsight. In 1783, while the Treaty of Paris ending the Revolutionary War was still being negotiated, General George Washington wrote to a committee of the Continental Congress laying out a plan for demobilization and the establishment of a peacetime military force. At its peak during the war, the Continental Army numbered 48,000 men, augmented by a much larger militia force.⁷ At the end of the war, Washington asked for a force of 2,631 regular soldiers. Realizing that Congress would expect even deeper reductions, he warned, “It is better to reduce our force hereafter, by degrees, than to have it to increase after some unfortunate disasters may have happened to the Garrisons.”⁸

In the same letter, Washington laid out the first plans for mobilization readiness. He called for all men age 18–50 to be registered on the states’ militia rolls and for the establishment of common standards, structures, and rules across the various militias. He also asked Congress for arsenals to store military equipment and supplies, and he called for “the Establishment of Military Academies and Manufacturies” that would “keep alive and diffuse the knowledge of the Military Art.” Washington emphasized that certain specialized roles were indispensable for a peacetime military, noting that “a Corps of able Engineers and expert Artillerists cannot be raised in a day, nor made such by any exertions, in the same time, which it would take to form an excellent body of Infantry from a well regulated Militia.”⁹

Congress debated the issue, and in June 1784, it authorized a total of just 80 soldiers in the Continental Army, with 25 to be stationed at Fort Pitt in western Pennsylvania and 55 at West Point along the Hudson River in New York.¹⁰ In parallel, Congress decommissioned the remaining US Navy ships, with the last vessel, the USS Alliance frigate, sold at auction in 1785.¹¹One member of the Continental Congress remarked at the time that “Until Revenues for the Purpose can be obtained it is but vain to talk of Navy or Army or anything else.”¹²

The War of 1812 was the nation’s first major test of mobilization readiness, and the results were mixed at best. When the war began, the Army had fewer than 7,000 soldiers in its ranks, and by the peak of conflict two years later, it numbered more than 35,000, supplemented by an estimated 458,000 militiamen.¹³ Congress reestablished the Army’s quartermaster and commissary departments that it had cut a decade earlier and created the Army’s Ordnance Department.¹⁴

After the War of 1812, the cycle of demobilization and mobilization continued through the Mexican-American War and the Civil War. The Union mobilization at the beginning of the Civil War is particularly noteworthy for the many “blunders, delays, and failures” that ultimately led to success.¹⁵ The War Department was slow to prepare for the coming conflict and vastly underestimated its magnitude once the war began. In June 1861, nearly two months after the battle at Fort Sumter, the head of the Army’s Ordnance Bureau reported the government had as yet purchased no muskets, that the Springfield armory was making only 2500 arms a month, and that the service lacked rifled muskets, accoutrements, artillery, and ammunition.”¹⁶

Civil War mobilization proceeded at an unbalanced pace, with the rate of manpower mobilization greatly exceeding the rate of arms production. Lacking government arsenals and private manufacturers that could produce large quantities of matériel quickly, the federal government was forced to contract with many smaller vendors, creating a procurement and management nightmare for the War Department.¹⁷

The pattern repeated itself decades later when the United States formally declared war on Germany in April 1917. In May of that year, Congress passed the Selective Service Act of 1917, creating a national conscription system. Within months, military manpower had grown by an order of magnitude.¹⁸ As in the case of the Civil War, however, the growth in manpower outpaced the military’s ability to equip the troops. US industry was again unprepared for military mobilization, and only 10 percent of the artillery and tanks and 20 percent of the aircraft used by American forces in World War I were made in the United States. The slow pace of mobilization also meant that US troops did not enter major combat in large numbers until the summer of 1918.¹⁹

Following World War I, the United States once again demobilized, this time from a peak of 2.9 million active-duty service members down to a force of around 250,000 personnel, the level at which it remained through the mid-1930s.²⁰ As policymakers became increasingly concerned the United States would be drawn into another war in Europe, mobilization efforts began much sooner than in previous conflicts. Industrial mobilization had a head start this time, having ramped up production to support allied forces well before the United States entered the war. This meant, however, that the US military itself remained under-equipped. When France fell to Germany in June 1940, for example, the US Army Air Corps had approximately a tenth of the planes Germany possessed and no heavy tanks. As in past mobilizations, the rate of increase in manpower exceeded the military’s ability to equip its personnel, with troops being forced to train with sticks in place of guns in some cases.²¹

Despite two decades of planning, World War II mobilization was far from smooth—a sobering reminder that even deliberate preparation can fall short.²² Moreover, the underlying conditions that facilitated mobilization at the time—a large and underutilized industrial base and relatively insulated supply chains—are not easily replicated today.²³ Modern weapon systems rely more on globalized supply chains and higher technological complexity, and production lines have limited excess capacity.

Some have called this early period of US military history—which includes seven major cycles of mobilization and demobilization from the Revolutionary War through World War II—a tradition of unreadiness. While that was undoubtedly true, it was also a time in which the United States gradually learned how to effectively mobilize and responsibly demobilize.

Demobilization at the end of each conflict gradually became less deep, with the post-conflict size of the military remaining larger than its pre-conflict size.²⁴ The military retained more of the enabling functions, such as the quartermaster and ordnance offices, during each demobilization period. The US government also evolved in its ability and willingness to leverage its economic and demographic resources: issuing war bonds, levying increasingly expansive war taxes, and eventually creating a national conscription system. Perhaps the most important lesson learned from this period is that it is much faster to draft new recruits than to equip them.

After World War II, however, many of these hard-earned lessons seemed to fade from policy discussions. An implicit assumption underlying Cold War defense strategy was that war would be fought quickly and decisively with the forces at hand, both active and reserve components. Strategic mobilization still mattered, but only if the nation could survive an initial exchange of devastating nuclear attacks. In the post–Cold War era, planning shifted even more to focus on the deployment of forces and the activation of National Guard and reserve units to supplement active component forces (operational mobilization) rather than the ability to create new forces or scale industrial production.

The history of US mobilization experience reveals a consistent truth: Strategic mobilization success depends on factors beyond the military alone. Mobilization readiness shapes how quickly and completely a nation can convert latent capacity into military power—and at what cost. Four fundamental factors drive mobilization readiness: economic strength, workforce capacity, industrial capacity, and political will. Understanding these factors, key indicators to watch, and how they interact is essential for assessing the readiness to mobilize for large-scale, protracted conflict in the modern era.

Economic Strength

Economic strength is the foundation of mobilization readiness. Wars are won not only by armies but also by the economies that support them. A strong economy creates surge capacity—the ability to rapidly increase defense spending in a crisis—and historical data suggest that the theoretical maximum defense burden the economy can support is about 35 to 45 percent of GDP. This is a rough empirical ceiling based on historical data, and the actual ceiling would vary by nation, war duration, external aid, and many other factors.

US defense spending has exceeded 10 percent of GDP only four times: It reached 13 percent during the Civil War, 16 percent in World War I, 43 percent in World War II, and 14 percent in the Korean War.²⁵ Data assembled by the Stockholm International Peace Research Institute (SIPRI) show that Kuwait holds the record for defense spending as a share of GDP in modern times: 117 percent in 1991 during the First Gulf War. However, this is an outlier in the data because it appears to include reimbursement payments to the United States.²⁶ The second-highest spending level in the SIPRI data is Ukraine’s, at 37 percent of GDP in 2023. The handful of years reported for Eritrea show that its spending peaked at 34 percent of GDP in 1999, and the next highest is for Israel, at 30 percent in 1975.²⁷

Because defense spending surge potential is a function of economic size, the more an economy grows, the higher the potential spending becomes. Two key indicators to watch are the economic growth rate and the growth rate in per-person military costs (total defense spending divided by the number of active-duty military personnel). The second indicator is important because when the cost per person grows faster than the economy, it indicates an erosion in buying power that reduces the size of the force that the theoretical maximum level of spending can buy.

The government’s fiscal strength also limits surge capacity because high government spending and low revenues in peacetime leave less room for defense spending in wartime. Competing commitments in the budget—such as health care and retirement programs—effectively constrain fiscal options. Key indicators of fiscal strength are total government outlays and revenues as a share of GDP. When outlays or revenues exceed historical norms in peacetime, additional defense spending in a crisis can force painful trade-offs in domestic priorities that can erode public support.

Rapid and abundant access to credit also affects a nation’s fiscal ability to mobilize. Every major war the United States has fought relied heavily on borrowing to finance defense spending. Former Chairman of the Joint Chiefs of Staff Admiral Michael Mullen once warned that “our debt is the greatest threat to our national security. If we as a country do not address our fiscal imbalances in the near-term, our national power will erode.”²⁸While there is no clear limit to how much a nation can borrow, either in absolute terms or as a share of its economy, Admiral Mullen’s warning is instructive: Policy decisions that undermine government creditworthiness by accruing excessive debt or threatening default on that debt put military mobilization readiness directly at risk.

Key indicators of borrowing capacity include the debt-to-GDP ratio (overall debt burden) and the gross financing needs–to–GDP ratio (fiscal flexibility within the budget). Research suggests that a debt burden of more than 90 percent of GDP lowers economic growth, which in turn dampens the long-term capacity to rapidly increase defense spending.²⁹The gross financing needs-to-GDP ratio measures the sum of new borrowing, maturing debt, and interest payments each year as a share of GDP. This is a key liquidity metric showing how much of the government’s annual revenues are already committed to debt-related costs, which can crowd out defense spending.

Bond-yield spreads and interest-growth differentials also provide early warning signs of fiscal fragility. The bond-yield spread is the difference between the interest rate at which a country borrows and a risk-free interest rate, reflecting the market’s perception of government default risk. A widening spread can signal increasing fiscal stress or loss of confidence— an early warning of a potential debt crisis. The interest-growth differential is the difference between the average interest rate on government debt and the growth rate of the economy. When interest rates outpace economic growth, debt tends to expand relative to GDP, leading to a higher debt-to-GDP ratio and lower economic growth prospects.

Workforce Capacity

While economic strength provides the financial foundation, mobilization readiness also depends on putting that strength to work—soldiers at the front and workers in the factories. Workforce capacity is the human foundation of mobilization readiness, and it rests on four key factors: demographics, eligibility standards, conscription, and skills.

The working-age population is the raw material of workforce mobilization. Its size and composition determine the pool from which military manpower and industrial labor are drawn. Nations with a large working-age population, generally age 18–65, have a greater potential workforce for mobilization. While not all working-age people work or can work, a national crisis can create the incentives and opportunity for more citizens to enter the labor force. Importantly, domestic policies and funding for education, health care, childcare, and related services can strongly influence the overall size, skills, and ability of working-age adults to participate in the labor force.

Military manpower draws from a subset of the working-age population. The qualifications for military service define how narrowly the military draws from the overall labor pool. The US military’s eligibility requirements vary across the services in terms of age, educational attainment, citizenship, physical standards, and security requirements. While all the services have a minimum age requirement of 17 years, the maximum age at enlistment varies from 28 in the Marine Corps to 42 in the Space Force, although some waivers exist.³⁰ The Space Force is also the only service that requires all recruits to be US citizens, reflecting the near-universal clearance requirements of Space Force jobs.³¹

Unlike demographics, which can be influenced only gradually and indirectly over time, eligibility standards are elastic. Policy—not biology—determines how wide the recruiting aperture can open in wartime. One of the most numerically consequential policy choices affecting the pool of potential military recruits is whether and how women are allowed to serve. Excluding women from military service effectively cuts the potential number of recruits in half.

Other exclusions based on age, religious practices, health, criminal history, and other factors are also a policy choice, not a hard constraint. Nations can and often do revisit these exclusions when recruiting is pushed to the limit. For example, when the US Army faced recruiting challenges in 2006 during the conflicts in Iraq and Afghanistan, it widened its pool of potential recruits by accepting personnel with visible tattoos, minor medical issues, and misdemeanor convictions.³²

Full-scale strategic mobilization rarely relies on volunteers alone. Military conscription fell out of favor among many Western democracies in past decades, but more recent trends show a return to conscription. Among the Baltic states on NATO’s eastern front, Latvia resurrected the draft in 2023, Lithuania reintroduced conscription in 2015, and Estonia, which never eliminated conscription, extended draftees’ service commitment.³³ Israel, which already had a universal military service requirement for men and women, eliminated exemptions for ultra-Orthodox Jews in 2024 after decades of legal disputes.³⁴ In recent years, the US Congress has debated expanding the Selective Service System to include women but, as of this writing, has not enacted such a change.³⁵

Ukraine’s use of conscription provides insight into the role and evolution of conscription in modern warfare. Following its independence from the Soviet Union in 1991, Ukraine retained its mandatory conscription model, although over time it shortened the service commitment from two years to one. In 2013, it ended conscription entirely, only to reinstate it the following year when Russia invaded Crimea.³⁶ When Russia invaded again in 2022, the conscription system in place applied only to men age 27–60, the reverse of the US Selective Service System, which applies only to men age 18–25.³⁷ After two years of fighting, Ukraine lowered the mandatory service age to 25 and began requiring all men age 18–60 to register, creating the potential to further lower the age in the future.³⁸

The resurgence of conscription may seem at odds with a future warfighting environment that is increasingly dominated by uncrewed, autonomous, and AI-driven weapon systems. But recent conflicts indicate that manpower remains indispensable to military power. The US military’s experience in uncrewed aircraft shows that these systems do not reduce personnel requirements—they are just as manpower intensive as their crewed counterparts. And without human restrictions on the platforms themselves, uncrewed systems (and their operators and maintainers) are often used more frequently and for longer-duration missions.³⁹ As one scholar noted, “Rather than eliminating the need for soldiers, new technology has created new demands—for cyber, space, and other expertise— that previously did not exist.”⁴⁰

The demand for both quantity and quality personnel naturally leads militaries to adjust standards and even recruit foreign fighters to supplement domestic forces. Ukraine has openly recruited volunteers from abroad to join its military ranks in the conflict with Russia, and Russia has used mercenary forces from Nepal, India, and North Korea, albeit with mixed results.⁴¹ Foreign fighters can offset demographic shortfalls and make more domestic personnel available for industry—a reminder that mobilization is a whole-of-society endeavor.

Industrial Capacity

While economic strength and workforce capacity provide the financial and human inputs for mobilization readiness, industrial capacity is the engine that converts these inputs into warfighting matériel at the speed and scale that the strategy requires. Industrial capacity matters because it sets the upper limits of how fast the military can field equipment and how long it can sustain a high operational tempo—including the munitions expenditure and platform attrition rates that the tempo requires. High-intensity conflict consumes precision-guided munitions and other expendables at rates that can quickly outstrip existing stockpiles and production capacity.⁴² The combination of access to raw materials, defense-relevant production capacity, and innovation capacity determines how rapidly a nation can produce weapons, sustain output under stress, and adapt to changing threats. History shows that even nations with strong economies and large populations can falter if their industrial base is brittle or misaligned with wartime demands.⁴³

Geography creates asymmetric advantages and disadvantages. Nations rich in minerals, arable land, energy resources, and natural harbors and rivers have a potential mobilization advantage that less geographically fortunate nations cannot easily replicate. In the modern era, rare earth metals have become a key focal point in defense policy debates because of their unique electromagnetic and optical properties and China’s dominance of their production and processing.⁴⁴ Energy production and distribution are increasingly important as well, to power not just the factories that build hardware but also the data centers and AI tools needed to design and exploit military capabilities. As military capabilities become increasingly data centric, data center capacity may become a limiting constraint in the ability to scale force structure and operational tempo.

Stockpiles can serve as a buffer that buys time during supply disruptions or while production ramps up. During the Cold War, the United States maintained a large and diverse stockpile of more than 70 critical materials, from aluminum and asbestos to vegetable tannin extract and zinc. The size and composition of the national defense stockpile have evolved with shifts in the security environment, funding constraints, and the offshoring of US manufacturing in many sectors. The utility of stockpiling, however, is ultimately limited by industry’s ability to process and use the materials.

Production capacity and latency—the ability to build hardware and software at scale and the time it takes to increase production—are important constraints on mobilization because they set the maximum speed for force structure growth and operational replenishment. Weapons optimized for performance may also be difficult to produce at scale compared with designs that prioritize manufacturability and modularity. Strategy can demand a high production rate on short notice, but industry can deliver only at the rate peacetime budgets have preserved.

As Jacques Gansler once observed, the increased complexity of weapons requires precision manufacturing, longer lead times, and higher skill levels to build and operate, which drives unit costs up and quantities down. He noted, “The result of buying fewer, more expensive systems is that the peacetime defense industrial base cannot achieve high production rates or be easily maintained for future emergency surge demand.”⁴⁵

This trend of buying fewer platforms at higher unit costs also feeds a readiness death spiral. Higher unit costs drive force structure reductions, which increases operational demand on the forces that remain, which raises operational costs even higher, and leads to further force reductions. The effect on mobilization readiness is twofold: A smaller force relies more on mobilization in a crisis, yet industry has less capacity to scale production, even if the spigot of spending is opened wide.

Since the Cold War, three dynamics have reshaped the US defense industrial base in competing ways: massive horizontal consolidation in industry, a private-sector surge in research and development (R&D) investment, and the emergence of a new generation of vertically integrated prime defense contractors. In what became known as the “last supper,” Secretary of Defense Les Aspin convened all the leaders of major defense companies at a dinner meeting in the fall of 1993. Norm Augustine, chief executive officer of Martin Marietta at the time, recalls that “the Defense Department was saying there are way too many companies in the defense industrial base” and “that we couldn’t have a bunch of companies with half full factories and not enough money to invest in research and development, huge overhead, high costs.”⁴⁶ This highlights an inherent tension in mobilization readiness: Half-full factories may be wasteful and inefficient in peacetime, but they provide the surge capacity the nation needs in wartime.

The post–Cold War defense consolidation was largely horizontal integration that reduced surge capacity in the name of efficiency. Companies that once competed for contracts merged into larger conglomerates, and these larger companies kept merging and acquiring one another until just five or six major prime contractors were left. Each maintained a wide range of defense capabilities, but after years of consolidation, the overall capacity of industry was much less than before.

A further complication was the increasing reliance on small and mid-tier companies that worked almost exclusively as subcontractors to the primes. While the Department of Defense (DOD) has a high degree of insight into the prime contractors it uses and how they perform, it has much less insight into the prime contractors’ subcontractors—and even less insight into the subcontractors to the subcontractors. What this means in practice is that multiple primes may bid on a major weapon system, giving the appearance of real competition, but each prime may be depending on the same subcontractors for key components, creating the potential for critical supply-chain vulnerabilities and throughput choke points at the second and third tiers of the industrial base.⁴⁷ In a modern mobilization, the binding constraints are likely to be less final assembly than the upstream bottlenecks—specialized suppliers, scarce skills, software integration, and critical materials—that cannot be surged quickly without sustained peacetime investment.

While the horizontal consolidation of the 1990s and early 2000s reduced competition and overall industrial capacity, a mitigating factor began to emerge from the democratization of technology. As shown in Figure 1, private investment in R&D began growing much faster than government R&D spending in the 1990s. After decades of private-sector R&D spending growth outpacing government R&D spending, the center of gravity for innovation in many important sectors has moved from the government to the private sector. Instead of DOD spinning off technologies that could be used for commercial purposes, the military is increasingly adapting commercial technology for defense applications.

A nation’s innovation base governs the rate at which it can develop new capabilities and adapt to counter an adversary’s capabilities. The democratization of technology means that more people and companies in the private sector have access to design tools and other enabling technologies that make rapid innovation possible, which naturally expands the innovation base. While this can level the playing field for adversaries with access to the same commercial technology, it can be a net advantage for the United States and its allies because it relies on several fundamental strengths inherent in free-market democracies: access to private capital, private property rights, a culture of entrepreneurial risk-taking, and open societies that attract talent.

Another trend became apparent in the first decade of the 2000s with the emergence of a new generation of defense companies—the “neo-primes” like Palantir, Anduril, and SpaceX—fueled by venture capital and private equity investment. Rather than relying on the US government to define requirements and fund the development of new technologies, these companies use private capital to develop new technologies in anticipation of requirements, accepting more risk to innovate faster.⁴⁸

One of the ways some neo-primes have accelerated the pace of innovation is through the vertical integration of their supply chains. Rather than relying on large networks of subcontractors, which themselves rely on even more subcontractors, vertically integrated companies develop more capabilities in-house.

SpaceX is perhaps the poster child of this approach. Unlike many legacy space companies, it builds nearly everything itself, from the engines used on its launch vehicles to its flight control systems and launchpads. Over time the company expanded to build satellites, laser communications links, consumer-grade ground terminals, and even spacesuits for astronauts. Other companies, such as Blue Origin, Rocket Lab, Relativity Space, and Planet Labs, have also adopted vertical integration, perhaps proving that this approach is ideal for the space sector.⁴⁹

One of the main advantages of vertical integration is design iteration speed. When engineers need to make design trades in a vertically integrated company, they don’t have to navigate through layers of subcontractors and potentially renegotiate contracts. Trades can be made internally and dynamically as designs mature and tests produce more data. Vertical integration makes it possible to rapidly iterate the design-build-test process, but it requires a high degree of tolerance for risk and failure.⁵⁰

The net effect of vertical integration on mobilization readiness, however, is mixed. While vertically integrated companies may innovate faster and be more adaptive to changing requirements, the tightly integrated and proprietary nature of their designs can make it more difficult to scale production beyond a single firm’s capacity. Other companies cannot easily build a competitor’s design, which limits the military’s ability to leverage available capacity from other suppliers.⁵¹ Vertically integrated companies may also find themselves locked into specific types of products, unable to pivot to fundamentally different products if demands change.

Importing arms from abroad can mitigate deficiencies in a nation’s industrial capacity, provided a government has the financial ability to do so. Imports use the raw materials, energy, and production capacity of others to effectively expand a nation’s industrial capacity. Imports also use foreign labor, which frees up domestic workers for other priorities, such as staffing military units. Offshoring weapons production in wartime can leverage an economic advantage to offset weaknesses in workforce or industrial capacity. However, arms imports are constrained by allied stockpiles and production capacity, contested logistics, export controls, and partners’ competing wartime demands.

Political Will

The political will to mobilize is closely related to the political will to fight. Mobilization is often an early indicator of what costs the public is willing to bear— especially if these costs are not distributed evenly across a nation’s citizens. It determines whether leaders and the public are willing to support higher defense spending, labor reallocation, military conscription, and industrial disruptions. If industrial capacity is the engine that determines the maximum rate at which a nation can convert funding and labor into warfighting matériel, political will determines when that engine is started and how hard and how long it is driven. Three drivers are central for understanding political will: threat perception, civilian and military leadership, and social cohesion.⁵²

The public perception of threats and the stakes involved inform what level of mobilization readiness is politically feasible. Higher defense spending forces real trade-offs—some combination of cuts to other government programs, higher taxes, and increased borrowing—that can erode public support. Research has shown that the public will sustain steep sacrifices for perceived existential threats, but it may resist even modest trade-offs for threats viewed as discretionary.⁵³

Leadership in and out of government shapes political will by framing threats, signaling urgency, and sustaining public support. Leaders face a dilemma in discussing threats: They must share information on threats and demonstrate the credibility of the evidence while protecting sources and methods. If the information they share turns out to be inaccurate or based on flawed analysis, it can fatally undermine public trust. And if they provide too little evidence to justify mobilization readiness costs, the public may never buy into the threat. In the modern information environment, social media can accelerate the spread of competing narratives, making public support for mobilization more volatile and harder to sustain over time.

Military and civilian leaders also play an important role in steering government institutions. While military leaders help define mobilization requirements and objectives—what is needed for mobilization— only civilian political leaders at the highest levels can coordinate across government agencies. Civilian leaders must lay the political groundwork for strategic mobilization, such as establishing a national conscription system and the legal authorities needed for national emergencies. The Franklin Roosevelt administration and Congress, for example, started preparing for mobilization well before the attack on Pearl Harbor brought the United States into World War II.⁵⁴

Another important element of political will is a nation’s social cohesion and capacity to sustain collective sacrifice. RAND Corporation researchers define cohesion as a “shared sense of purpose within a group of government leaders and elites” where even opposing political groups can find agreement.⁵⁵ (Emphasis in original.) Economic and fiscal issues, such as slow growth, high taxes, burdensome debt, or excessive peacetime spending, can make it more painful and disruptive to mobilize. Similarly, poor government policymaking and management decisions can undermine perceptions of fairness and legitimacy—especially when the burdens of mobilization appear unevenly distributed.

Public polling data, when available, can provide insight into a nation’s political will. Opinions of potential threats, government institutions, and political leaders can identify issues that may undermine political will, and longitudinal tracking of these data serves as an early indicator of shifts that may affect the ability to mobilize.

One of the key indicators of social cohesion is the level of inequality in a country. The Palma ratio measures economic inequality by comparing the income earned by the top 10 percent with that earned by the bottom 40 percent.⁵⁶ In past wars, perceptions of inequality contributed to a loss of trust in institutions and processes, as occurred with the conscription system in the Vietnam War and accusations of defense company “profiteering” in nearly every war in American history. As Stuart Brandes argues, Americans have struggled since before the Revolutionary War with how to fairly “distribute the burden of mobilizing economic resources for military purposes.”⁵⁷

Importantly, the credibility of mobilization readiness as a deterrent depends on external perceptions of political will. Adversaries and allies must believe the nation would bear mobilization costs in a crisis. A nation with high political will—where threats are perceived as legitimate and existential, leadership is strong, and social cohesion is high—can sustain the level of shared sacrifice that high-intensity, protracted conflict demands. Without political will, latent economic, workforce, and industrial potential may be high, but the public may prove unwilling to mobilize.

Key Indicators

Like other types of readiness, mobilization readiness cannot be accurately captured in a single value or stoplight chart. An additional complication is that the potential for mobilization cannot be directly measured but must instead be inferred and bounded by other data. It requires a basket of economic, workforce, industrial, and political indicators that each illuminate different aspects of a nation’s capacity to mobilize. And because mobilization readiness is a whole-of-society effort, it can be measured at only the national level.

Table 1 lists candidate indicators for understanding a nation’s mobilization potential over time and relative to other nations. Many of these indicators depend on context: Actual mobilization ability depends on the specific circumstances in which a crisis occurs, and a crisis can significantly affect many of the indicators themselves.

Importantly, one should not attempt to combine these indicators into a single composite index for mobilization readiness. Any weighting and aggregation across dissimilar measures would require analytically suspect normative assumptions and would risk masking the specific advantages and constraints the data may reveal.

It is possible, however, to define “stress bands” for selected indicators to flag when they depart from historical norms or projected wartime demands. For example, a stress band for government outlays and revenues as a share of GDP could be when these measures exceed their historical mean by more than one standard deviation, measured over a relevant baseline period, such as the post–Cold War era. Industrial capacity in particular should be closely tied to scenario-based analysis of likely wartime demands.

Conclusion

Mobilization readiness is the foundation on which other types of readiness are built and the limiting factor for how fast the military can expand, how large it can become, and the operational tempo it can sustain. Mobilization readiness determines how fast a nation can convert its resources into military power. For most of its history, the US military relied on mobilization readiness because it deeply demobilized at the end of major wars. While the United States has maintained a sizable peacetime military since the end of the Korean War, the prospect of large-scale, protracted conflict has brought renewed attention to mobilization readiness and what it requires in the modern era.

Economic strength sets the overall potential for surge funding but faces practical ceilings and political trade-offs when overall government outlays, revenues, and debt run high. Workforce capacity provides both soldiers and industrial labor and is shaped by demographics, military standards, conscription mechanisms, and worker skills. Industrial capacity is the engine that converts funding and labor into weapons, constrained by raw materials, latent production capacity, and innovation capacity. Political will is the throttle that determines when and how fast the nation is prepared to mobilize and the sacrifices it is willing to sustain.

The United States has not experienced a full-scale strategic mobilization since World War II. Given the current threat environment, the question strategists should be asking is: What would a modern-day strategic mobilization look like? The US economy is far larger in real terms today than it was in 1940, but the fiscal and debt situation is much worse. The working-age population has increased as well, but the military has not used conscription for two generations. Private industry is larger and more technologically sophisticated than ever, but the US manufacturing sector has declined as a share of the overall economy.⁵⁸ Political will is constantly shifting and situationally dependent, but deep political and societal divisions, combined with lingering mistrust from unpopular wars in the recent past, could undermine support for a future conflict. The United States may be at the cusp of a new readiness tradition in which mobilization readiness again becomes central to deterrence and warfighting.

Mobilization readiness can be a powerful deterrent for large-scale conflict, but only if it is credible and offers a relative advantage over potential adversaries. If an adversary believes it can achieve a fait accompli before the United States can fully mobilize, latent capacity alone will not suffice. Deterrence requires visible peacetime investments that signal the ability to surge quickly and sustain the effort.

The 2026 National Defense Strategy raises an important question: Could an adversary such as China out-mobilize the United States? More precisely, does China believe it has a mobilization advantage over the United States in a protracted conflict? The decisive variables in this calculus are speed and scale—the upper limits on how fast and how large the military can grow to overcome deficits or sustain an advantage in structural, operational, and modernization readiness. The United States can improve its mobilization readiness in many ways, but the steps it must take—from reducing the annual budget deficit to funding excess production capacity in peacetime—can be paradoxical and require sustained political sacrifice.

About the Author

Todd Harrison is a senior fellow at the American Enterprise Institute, where he focuses on defense strategy, defense budgeting, and space policy.