From the rout of Union forces at Bull Run to two decades of counterinsurgency in Iraq and Afghanistan, history tells us that our assumptions about future war are often incorrect. Looking to today, consider this view of a potential US-China conflict:
Any confrontation between the United States and China would be short and intense, decisively determining the war’s outcome in a matter of days or weeks.
How often has this assumption informed past discussions in the Pentagon and Washington’s think tanks? Three years of attritional war in Ukraine and stubbornly persistent security challenges in the Red Sea call this sentiment into question, causing defense commentators to reexamine the possibility that despite both nations being nuclear armed, a US-China war may not end in days or weeks, but could protract for months or even years. This raises the question: How many other assumptions about great power war are due for reexamination?
At the Center for Strategic and Budgetary Assessments, we have conducted dozens of exercises on the strategic choices facing political and military leaders regarding the revitalization of the US military for great power war. These exercises often highlight how fighting a prolonged war calls for a different approach than shorter campaigns, such as choosing to expand defense production over relying on existing stockpiles. Regardless of the participant, some form of industrial mobilization is frequently considered the key for unlocking greater production in long wars.
Admittedly, no one can know the exact character of a future war between the United States and China, but recent CSBA research on US mobilization planning during the interwar period gives reason to question some oft repeated assumptions. Comparing current planning assumptions to those of the interwar period reveals several instances where our expectations may fall short of the realities of war, protraction, and mobilization. Today’s security environment, economic circumstances, and military forces may be a world apart from those of the 1930s, but planning to wage war in the American system is fundamentally the same in many ways. For this reason, the US experience in World War II should inform our thinking regarding a future US-China conflict. Five frequently recurring and often implicit assumptions about protracted war stand out, and the American historical experience suggests they may be due for reconsideration.
Assumption 1: The opening battle would determine the outcome of the war.
Maybe—or maybe not. The United States Pacific Fleet was attacked at Pearl Harbor and the US Army ceded the Philippines to Japan by the summer of 1942. Huge swathes of Western Europe fell prey to Nazi invasion and occupation before being liberated years later.
Similarly, the loss of Taiwan or other Chinese military moves in the Indo-Pacific might not determine the outcome of the broader war they could trigger. Unless the United States or China suffer irreparable attrition or domestic pressures force leaders to cut losses, war may continue long after an opening engagement. For this reason, US decision-makers must weigh risk to force against risk to mission in any Indo-Pacific action. Committing the US military to an opening battle that sacrifices its longer-term global position is not a winning protracted war strategy.
Assumption 2: Once a conflict begins, the US industrial base will rapidly expand into the arsenal of democracy and provide the goods required for prevailing in a protracted war.
Our understanding of America’s World War II mobilization is due for an update. Interwar planners spent twenty years after World War I thinking about industrial mobilization. President Franklin D. Roosevelt started mobilizing in a limited fashion two years prior to Pearl Harbor, and the US military was still ill-equipped to wage war at the necessary scale until 1943, nearly five years after mobilization began.
Moreover, the enabling conditions of US industrial mobilization for World War II no longer exist. Globalization has fueled US deindustrialization. The degree to which this will limit the expansion of war production is unclear. If recent efforts to supply Ukraine are any indicator, then increasing US war production today will require more time than it did in the late 1930s. The United States no longer possesses the raw industrial might of the 1940s; today’s defense industry is more brittle than during the Cold War; and contemporary weapons are exceedingly more complex and harder to manufacture than those of World War II. These changes point to the need for novel mobilization planning that accurately links manufacturing timelines and operational plans.
Assumption 3: After the proverbial balloon goes up, resources will be infinite and any politics that impede defense procurement and production will be pushed aside.
Again, a reductionist and rosy impression of the nation unifying to fight World War II obscures the gritty reality of bureaucratic infighting, investigations into defense spending, and numerous labor strikes that delayed war production. Even when the fiscal spigots were opened after Pearl Harbor, the US strategic approach remained constrained by basic national limits on raw materials and manpower, which had to be shared between the military and industry. American leaders were forced to accept a US Army of three hundred thousand fewer men (and significantly less armor) than desired, delay major campaigns, and choose between building factories or weapons.
A contemporary great power war would not eliminate the need for convincing Congress to authorize and appropriate resources. It would not eradicate all bureaucracy and regulatory regimes. It would not immediately resolve disputes between the military, industry, the workforce, and other interest groups. And even unprecedented boosts in defense spending would not remove fundamental shortfalls in raw materials, critical infrastructure, transportation capacity, and the workforce. Ukraine and Russia have both demonstrated a continued reluctance to fully mobilize, which shows how even during existential war, politics reign supreme and resources remain limited. It is up to the Department of Defense to work within these limits, mitigate risks where possible, and find creative solutions to enduring political and bureaucratic challenges.
Assumption 4: Without massive increases in defense spending, the Department of Defense cannot prepare the defense industrial base for expanded production or mobilization.
Activating the arsenal of democracy was massively expensive and required the mobilization of national resources on a level not seen before or (thankfully) since. But mobilization planning during the interwar period shows how effective peacetime preparations can be made even during periods of constrained resources. More money would have helped, but planners invested limited funds in preparing to expand production of the most essential military goods.
Mobilizing to fight a great power war against China would be similarly costly. That said, there are a variety of ways the department can prepare today. From mobilization and protracted war planning within the Pentagon to commissioning production studies or even educational orders with US commercial manufacturers, the department has numerous options. Similar efforts accelerated mobilization for World War II and could do so again.
Assumption 5: For a protracted war, we will just need more of (and the ability to produce more of) our current munitions, platforms, and systems.
The US military of 1945 was vastly different from that of 1940. From different platforms (the Sherman tank, the Essex-class aircraft carrier, and the B-29 bomber) to new organizations (mobilization agencies, the Office of Strategic Services) and novel missions (strategic bombing, large-scale amphibious invasion), the interaction between US objectives and the course of the war dictated new challenges, requirements, technologies, and institutions.
Contemporary planners must consider how the US military’s production needs will change over the course of a protracted war. Producing war materiel at scale may dictate design and production modifications or the development of entirely new classes of minimum-viable systems, such as the Liberty ship or M3 submachine gun. It is worth developing, testing, and experimenting with these systems before they are urgently needed. More immediately, planners must ensure the standing military is capable of fighting and sustaining losses until follow-on forces can be trained, equipped, and deployed.
The Pentagon may forever be planning to fight the last war, but when it comes to thinking about the next war, questioning long-held assumptions, taking an unbiased look at the historical record, and seeking perspectives from outside the beltway can only improve our chances of getting predictions right—and winning. There are always risks associated with over-applying the US experience in World War II. However, by looking into the past the Department of Defense may develop a more fulsome appreciation for great power war, its potential duration, and the need to address mobilization’s challenges rather than assuming them away.
Tyler Hacker is a research fellow at the Center for Strategic and Budgetary Assessments and a 2024–2025 research fellow with the Modern War Institute. He is the author of the report “Arsenal of Democracy: Myth or Model?,” which draws lessons for contemporary industrial mobilization from World War II. At CSBA, his work focuses on long-range strike and future operational concepts for great power conflict. He previously served as a field artillery officer in the United States Army.
The views expressed are those of the author and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.
Image credit: Eben Boothby, US Army Materiel Command