Our Prewar Era: America and the Dilemmas of Global Defense

In a 1942 essay, George Orwell wrote of the folly of refusing to believe that the most terrifying geopolitical nightmares can come true:

We in England underrate the danger of this kind of thing, because our traditions and our past security have given us a sentimental belief that it all comes right in the end and the thing you most fear never really happens. Nourished for hundreds of years on a literature in which Right invariably triumphs in the last chapter, we believe half-instinctively that evil always defeats itself in the long run.¹

That conviction, the product of Britain’s oceanic moat and Enlightenment traditions, had brought the country—and much of humanity—to the edge of the abyss in the worst moments of World War II. Were he alive, Orwell might see parallels in the American mindset today.

Most Americans alive now have known only a world structured, pacified, and made prosperous by unrivaled US power. For most Americans, then, it probably seems unthinkable that the international system could buckle under assault by revisionist states, much less that the next great-power war could end in a US defeat. That confidence is a testament to the world-altering success of US foreign policy since 1945. And it risks blinding Americans to their situation’s precariousness.

In every key region of Eurasia, revisionist states are aggressively contesting the status quo. They are gathering into an autocratic bloc more cohesive than anything the United States has faced in generations. But even as our moment increasingly resembles a prewar era, America is trapped in a post–Cold War mentality that risks leaving the nation overstretched and under-armed if a graver crisis strikes.

As a result, an alarming gap has emerged between America’s global commitments and ability to vindicate those commitments if they are tested. The world is becoming less stable. International affairs are becoming more violent. And the United States is running out of time to avoid its own geopolitical nightmare.²

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Throughout the modern era, struggles for global primacy have been struggles over Eurasia. That supercontinent is home to most of the world’s population and economic resources. It is where the most powerful countries on earth, America excepted, are found. Three times in the 20th century—during World War I, World War II, and the Cold War—the international system was convulsed by clashes between autocratic powers that sought primacy in Eurasia and coalitions led by offshore democracies—first the United Kingdom, then the United States—that fought to hold them back. A fourth such contest is now underway, as a new group of autocracies challenges the security of each of Eurasia’s vital regions.

In Europe, Russia’s assault on Ukraine easily qualifies as the continent’s most destructive conflict since World War II. The all-out Russian invasion in February 2022—merely the most intense phase of a struggle dating back to 2014—recalled the blatant land grabs and appalling atrocities that marked the worst parts of Europe’s 20th century. As of this writing, Russia had failed to conquer or dominate Ukraine. But Kyiv and its backers had failed to decisively defeat the invasion and, with it, Vladimir Putin’s project to overthrow the prevailing order in Europe and beyond.

Meanwhile, the war had produced global spillover, including violent Russian subversion in Europe, disruptions to world food and energy supplies, and geopolitical realignments from Scandinavia to northeast Asia. By late 2024, US observers from both parties were increasingly calling for a ceasefire.³ But the end of the war won’t end the threat from a hyper-revisionist, heavily militarized Russia with an epic grudge against the democratic world.

The Middle East is also a tinderbox. Hamas’s attack on Israel in October 2023 touched off a long, grinding war in Gaza and fomented violent instability from Lebanon to the Gulf of Aden. In the year thereafter, Iran twice attacked Israel with ballistic missile barrages massive enough to rate among history’s largest. The Houthis, with Tehran’s sponsorship and Beijing and Moscow’s complicity or encouragement, created the most sustained challenge to freedom of the seas since the 1980s.

To address these threats, Washington repeatedly rushed scarce resources—from missile defenses to aircraft carriers—back into a region it had spent the past decade trying to escape. Through resupply and other aid, it helped—sometimes grudgingly—Israel inflict sharp blows against Tehran and its proxies. But with Iran now a nuclear threshold state and even quasi-state actors like the Houthis having showcased a new level of capability, the crisis of Middle Eastern security is unlikely to be resolved anytime soon.⁴

East Asia isn’t wracked by a major hot war, but amid multiple regional cold wars, no one can credibly say the peace is secure. North Korea is racing ahead with its nuclear and missile programs, raising the threat to the American homeland and testing the cohesion of the US–South Korea alliance. China is coercing the Philippines in the South China Sea and increasing the military pressure vis-à-vis Taiwan. It continues to push ahead with a record-smashing, quarter-century military buildup featuring many of the capabilities needed to subdue Taiwan while deterring or defeating American intervention.

Moreover, Beijing is now engaged in a rapid-fire nuclear buildup, which will make it a strategic peer of the United States by the 2030s, and developing a blue-water navy and other tools to project Chinese power around the world. “Whatever its actual intentions may be, I could not say,” Secretary of the Air Force Frank Kendall warned in 2023, “but China is preparing for a war and specifically for a war with the United States.”⁵

As the Biden administration wound down, then, serious military conflicts afflicted two of Eurasia’s key theaters—the Middle East and Europe. In the third, maritime Asia, the danger of war was rising. Not since the early Cold War have instability and turmoil been so pervasive across the world’s central landmass. Not since the run-up to World War II has the risk of violent conflict engulfing all of Eurasia’s key theaters been so high. Even if there were no connections among the world’s malign actors, this scenario would severely test defense and deterrence for America and its allies. Still worse, the Eurasian revisionists—united by their intense hostility to American power and liberal ideals—are locking arms.

Surging global tensions have nourished autocratic partnerships. Moscow and Tehran have established a flourishing, two-way military relationship that bolsters Putin’s forces in Ukraine while arming and emboldening Iran in the Middle East. Russia and North Korea have signed a formal alliance that delivers vital arms and North Korean personnel to support Putin’s military while aiding Pyongyang’s advanced weapons programs and abetting its aggression.⁶

Russia and China unveiled their “no limits” strategic partnership just before Putin assaulted Ukraine. Since then, their economic and technological ties have expanded dramatically; their decades-old military relationship has become more substantive and, alarmingly, more secretive.⁷ Other revisionist relationships, such as between China and Iran and between Russia and the Houthis, are emerging or evolving. This isn’t a single, fully formed revisionist alliance. But it is an ever-denser network of ties connecting the world’s most malign states.⁸

These ties’ geopolitical effects are real, even if the details are sometimes hazy. Revisionist relationships hasten disruptive military innovation; for instance, China’s buildup has been aided by Russian weapons and, now, increasingly sensitive Russian technology. Such relationships reduce the isolation and punishment aggressors might otherwise face: A thoroughly sanctioned Russia has kept fighting in Ukraine thanks to Iranian and North Korean arms and strategic trade with China.

These partnerships raise the likelihood of violent instability on some frontiers by dampening it on others. Warm relations between Moscow and Beijing allow Putin to deploy most of his army in Ukraine and Xi to push harder for an advantage in the western Pacific. They also enable pernicious military learning: Consider how Iran mimicked Russia’s strike packages against Ukraine in its own drone and missile attack on Israel in April 2024.⁹

More profoundly, these relationships compound the chaos in today’s world, as colluding revisionist powers assault the international order from multiple sides; they even suggest that one aggressive state might aid, whether kinetically or non-kinetically, another revisionist state locked in crisis or conflict with the United States.¹⁰ Indeed, as relationships among America’s adversaries link the tensions across several theaters, they raise the risk that a conflict in one place could spread contagiously into others.

If that happened, it wouldn’t be the first time. Americans usually remember World War II as a global conflict. But it began as a set of regional crises—provoked by Germany’s push to rule Europe, Japan’s bid for conquest in China and then much of Asia, and Italy’s aggrandizement in the Mediterranean and Africa—that eventually merged and climaxed. In the 1930s and early 1940s, aggression on one front encouraged it on others: Italy’s invasion of Ethiopia encouraged Germany’s revisionism in Europe, which eventually tempted Japan to surge into Southeast Asia to exploit the plight of desperate or defeated colonial powers. To support their radical expansion programs, the fascist powers banded together in a loose alliance, the Tripartite Pact, thereby polarizing international politics and setting the world on fire.

Yes, the United States faces regional military challenges more severe and numerous than any in decades. But the real geopolitical nightmare is the danger that escalating regional crises could, once again, converge into a global war.

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Many American national security elites know there is a problem. The bipartisan National Defense Strategy Commission warned, in July 2024, that “the threats the United States faces are the most serious and most challenging the nation has encountered since 1945.”¹¹ Roger Wicker of the Senate Armed Services Committee likewise commented that “the United States is facing the most dangerous threat environment since World War II,” because an “emerging ‘axis of aggressors’ is working to undermine U.S. interests around the world.”¹²

On the campaign trail in fall 2024, the danger of “World War III” was a prominent theme.¹³ Think tanks and US government officials have issued a litany of stark warnings about the rising danger of conflict in the western Pacific and beyond.¹⁴ Yet the United States isn’t remotely prepared for the world it now confronts.

This may seem absurd, since the US defense budget is creeping toward $1 trillion. But don’t let the sticker price fool you. As a percentage of gross domestic product (GDP), US military spending is nearly as low as at any time since World War II.¹⁵

Per capita, the defense budget is roughly what it was in the mid-1950s, even though per capita income, adjusted for inflation, has skyrocketed since then.¹⁶ And although the United States still has the biggest military budget in the world, that budget is stretched by the demands of deterring a multitude of rivals and has hardly kept pace with inflation in recent years. This creates glaring problems in America’s global posture—not least its inability to cope with competing crises or conflicts.

This wasn’t always the case. In World War II, the United States fought intensely in several theaters simultaneously. For most of the Cold War, American planners believed the United States should be able to check enemy thrusts in at least two regions, even if Europe was the top priority. Following the Cold War, the Pentagon preserved a two-war strategy so it could wage and win near-simultaneous conflicts against regional powers such as Iraq and North Korea.

The rationale was simple and persuasive: A country with worldwide commitments needs a two-war military, lest conflict in one theater leave it unable to respond to aggression in another. As one Pentagon report put it, the two-war strategy was “the sine qua non of a superpower.”¹⁷

By the 2010s, however, America’s two-war strategy was coming undone. Part of the problem was that the world had changed. It was one thing to fight two relatively weak rogue states when America was at the peak of its post–Cold War primacy. It was entirely another to confront the great-power adversaries that emerged—or reemerged—a generation later.

Another part of the problem was persistent disinvestment in defense. In hindsight, 1991 to 2016 was one long post–Cold War drawdown, interrupted temporarily by a post-9/11 splurge mostly on counterterrorism and counterinsurgency. Then, the Budget Control Act of 2011 and the deep cuts it triggered slashed US capabilities just as threats were becoming more severe. The military and financial math of a two-war strategy had become unworkable, resulting in a bipartisan shift—which began under Barack Obama and was consolidated under Donald Trump and Joe Biden—to the one-war strategy America has today.¹⁸

The one-war strategy is meant to focus the Pentagon on developing the capabilities and concepts needed to defeat one peer rival, namely China, in a full-on conflict while deterring bad actors in other theaters—although how the US military will deter opportunistic aggression without the means to defeat it has never been adequately explained.¹⁹ This shift is because a big war with China would consume most of America’s global combat power and virtually all its strategic lift and logistics, likely straining the defense industrial base to the breaking point. That shift has forced the Pentagon to seriously consider how to project power into lethally contested environments, such as the first island chain, which runs from Japan to the Philippines. It has underpinned promising ideas, like the Replicator initiative, meant to marry mass and precision and thereby turn the western Pacific into a “hellscape” for Chinese forces.²⁰ Even so, the US military is beset by weaknesses that threaten its ability to win a single major war, let alone two.

Multiple studies have shown that the United States would quickly run short of long-range missiles, missile interceptors, and precision-guided munitions in a high-intensity conflict, with no good way of replenishing them.²¹ The Navy is struggling to keep enough attack submarines—perhaps America’s single greatest asset vis-à-vis China—at sea, let alone produce the desired quantity of new ones. The surface fleet is being run ragged because too few ships are trying to do too much across too many regions.²² The effort to simply update the US nuclear arsenal is stumbling, even as China’s buildup means Washington must soon deter two nuclear peers at once.

Things will get worse before they get better, since the Pentagon must retire many Reagan-era ships, submarines, and planes in the late 2020s, even though their replacements won’t arrive, in many cases, until the 2030s. Broadly, the Pentagon faces two painful dilemmas—between conventional and nuclear modernization and between investing in future capabilities and procuring existing ones—because it doesn’t have enough money to go around.²³ Many of those weaknesses, in turn, are rooted in the deep fragility of the defense industrial base, which limits America’s ability to prepare for war and replace lost or used equipment once the shooting starts.

These problems’ geopolitical effects are accumulating in real time. Through much of 2024, the Houthis created havoc in the Red Sea and mocked a superpower that supports freedom of navigation. Yet for months, the best Washington could do was a desultory tit for tat with the once-obscure extremists, because a more punishing, and potentially more decisive, campaign would consume America’s limited stockpiles of key munitions and leave it unprepared for a bigger war in the Pacific. But even America’s readiness for that one big war is increasingly questionable, as Washington’s principal adversary races to prepare itself for a fight.

China is engaging in ever-more-menacing military exercises around Taiwan. It is hoarding food and energy and otherwise reducing its vulnerability to sanctions. Moreover, China’s nuclear force doubled between 2020 and 2023, and its shipyards are churning out new vessels as its factories mass-produce missiles and bombs. As Seth Jones of the Center for Strategic and International Studies writes, “China now acquires weapons systems at a pace five to six times as fast as the United States.”²⁴

In a favorable scenario, the United States might still win a single war in the western Pacific, albeit at a horrifying price in lost planes, ships, and service members; the catastrophic disruption of key supply chains and trade routes; and serious risks of nuclear escalation.²⁵ But the balance of power is shifting so rapidly that America could well lose the next great-power war, and it would most likely be overwhelmed if it was forced to fight major wars—whether interrelated or not—in two or more regions at once.²⁶

Such a defeat’s geopolitical consequences could be momentous. It could well threaten the credibility and integrity of America’s alliance structure. If the US military was battered in a high-intensity conflict, Washington might lose, if only for a time, the ability and will to continue leading global affairs.

Overall, the world would probably change in ways presently hard to enumerate or imagine. After all, major wars have historically set the terms of global order. If America loses the next great-power conflict, it might have to get used to a world where some other nation makes the rules.

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Of course, the United States wasn’t ready for the biggest wars of the 20th century either. “Good Lord! You’re not going to send soldiers over there, are you?” one senator exclaimed after the United States declared war on Germany in April 1917.²⁷ It was a fair question, since America’s total land forces at the time numbered slightly more than 200,000. As World War II began, the US armed forces, which the retrenchment of the 1920s and 1930s had gutted, remained undersized, under-equipped, and under-trained. But America ultimately won that war, as it had won World War I, through an astounding, world-beating mobilization.

By the time the fighting ended in 1945, the United States had built more than 300,000 airplanes. In 1944 alone, American shipyards launched 2,247 naval vessels, a total that outstripped the rest of the world combined. American industry sustained the entire Grand Alliance: At Stalingrad on the eastern front and El Alamein in Africa, Soviet and British troops rode American tanks and trucks to victory.²⁸

US forces weren’t always the best on the battlefield, but their superiority in equipment and logistics was more than the Axis could overcome. “I cannot understand these Americans,” one German commander remarked. “Each night we know that we have cut them to pieces, inflicted heavy casualties, mowed down their transport. But—in the morning, we are suddenly faced with fresh battalions, with complete replacements of men, machines, food, tools, and weapons.”²⁹ This performance, as the great “arsenal of democracy,” has lasting resonance for Americans. It may lead them to think that, if the world goes to pieces, America will mobilize and manage the same feat again.

Alas, it isn’t so simple. One reason the United States mobilized so effectively in World War II was that it had a crucial head start: Its buildup began in earnest after the Munich crisis in 1938, a full three years before Pearl Harbor. US defense spending surged from well under 2 percent of GDP in 1938 and 1939 to over 5 percent in 1941.³⁰ In 1940 alone, the United States ordered nine battleships, 11 aircraft carriers, eight heavy cruisers, 31 light cruisers, and 181 destroyers—a fleet roughly the size of its entire navy today.³¹ Moreover, the United States could surge production because its economic dominance was based on its manufacturing dominance and because the Great Depression had created lots of temporarily idle capacity that could be activated once the money began to flow.

Much has changed 80 years later. China is now the world’s workshop, while America’s industrial base is plagued by choke points and weaknesses. Those who believe America can wait for the fighting to start and then rapidly and decisively win the wartime mobilization race are living in another era.

Other shortcuts to strategic solvency are just as illusory. Some argue America can slash its global burdens by shifting them to allies. True, those allies have a tremendous stake in the present order, which can’t be preserved unless they invest more in the common defense. But while some allies, such as Japan and Poland, are revolutionizing their defense strategies and military capabilities, too many others are still struggling to hit remedial spending targets or field forces remotely equal to the threats they face.³² If defending the free world must be a collective endeavor, it will fail if America simply tries to substitute its allies’ initiative for its own.

As officials from Tokyo to Canberra frankly acknowledge, no Indo-Pacific coalition can balance China unless the United States anchors it. Even in Europe and the Persian Gulf, where the material balance of power is more favorable, friendly countries would struggle to summon the capabilities and common purpose necessary to contain their enemies absent American leadership. Does anyone really believe, for instance, that the Europeans would have rallied to Ukraine’s aid in February 2022 had the United States simply left the matter to them? Or, as seems far more likely, would a divided and demoralized continent simply have made its peace with another Russian conquest? An America that tries to slough off responsibility to allies won’t enjoy greater security at lesser cost—it will find that its allies struggle to preserve a congenial global order if America itself is no longer committed to the task.

The same problem afflicts a final shortcut to solvency: focusing squarely on China and radically deprioritizing the rest of the world. It’s true, as the Biden administration has often said, that China is “the only competitor with both the intent to reshape the international order and, increasingly, the economic, diplomatic, military, and technological power to advance that objective.”³³ It’s also true that losing a war in the western Pacific would be one of the worst things that could happen to the United States. But a China-only approach is no answer to America’s global strategic dilemma.

For one thing, on the current trajectory, a few years from now, the United States might not be able to deter and, if necessary, defeat China even if it pulls back from other regions.³⁴ Thus, a China-only approach could provide a false comfort that undercuts any push for adequate defense spending—while still failing on its own terms in the end. Furthermore, such a strategy would come at a massive global cost.

In today’s conditions, pulling back from Europe and the Middle East would exacerbate violent instability in those regions, raising the odds that America must return later and under worse conditions. And America would have to return, because those regions still matter greatly. Europe has real economic heft and still contains the world’s largest concentration of liberal democracies; the Middle East commands vital energy resources, strategic geography, and the narrow waterways that connect Europe to Asia.

In the meantime, withdrawal from contested regions would raise grave questions—including in Asia—about America’s commitment and staying power. It would also severely complicate the task of rallying recently abandoned countries in Europe and the Middle East to push back against China’s worldwide influence. Even a global superpower must set priorities. But it can’t choose to compete in one theater while excluding the rest.³⁵

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Addressing America’s national security shortfall isn’t just a matter of money. Even an infinite budget wouldn’t relieve the United States of the need to fix a broken acquisitions process so the Pentagon can develop and field new capabilities more rapidly. Nor would it eliminate the need to develop operational concepts that allow the services to project power across vast distances and into crowded, deadly environments—nor the need to learn and incorporate the lessons from wars in Ukraine and the Middle East about the uses of uncrewed systems, the interaction between missiles and missile defenses, AI’s role on the battlefield, and the prospects for massing and maneuvering in a world of ubiquitous overhead surveillance. Most critically, even greater abundance doesn’t obviate the responsibility to make sound, sober decisions about how to deter and under what conditions to fight.

It bears restating that defending the international order is not solely an American responsibility. The United States and its allies must work toward higher spending thresholds and more ambitious capability targets in Europe and the Indo-Pacific. In the latter theater, especially, Washington must stitch various bilateral relationships together into a network that can more credibly promise and execute a collective defense.³⁶

Integrating industrial bases is also essential: The best near-term option for offsetting a daunting US deficit in shipbuilding, for instance, is to work more closely with allies, such as Japan and South Korea, that have their own real capacity.³⁷ America’s alliances are perhaps its greatest strategic advantage. More integration and collective effort among the democracies is the best response to the autocratic world’s intensifying coercion and cooperation.

But those alliances, and the larger liberal order, rest on a foundation of hard power—specifically, American hard power—which urgently needs to be strengthened. The ins and outs of a more expansive US defense program are the subject of other chapters in this book. But generally, the United States needs a level of defense spending that eases trade-offs between the present and the future; addresses critical near-term shortages in munitions and other capabilities; pays to expand production lines and increase the defense industrial base’s resilience; permits concurrent conventional and nuclear modernization; aids embattled friends, such as Ukraine and Taiwan, without unacceptable trade-offs for America’s own capabilities; and, broadly, builds the capability and capacity necessary to reduce the gap between America’s resources and the realities of a dangerous, disordered world.

The post–Cold War era is over. If America doesn’t start acting like it faces a national security emergency, historians will likely look back on this moment as a prewar era.

The cost, no doubt, will be substantial. Serious observers’ most aggressive proposals call for a defense budget equivalent to 5 percent of GDP (compared with slightly north of 3 percent today), with increases to be phased in over a few years so the Pentagon can effectively absorb new resources.³⁸ That’s a lot of money—call it $1.5 trillion annually. But it’s less, as a share of output, than the roughly 6 percent of GDP the United States spent at the height of the Reagan buildup; the 7.5 percent it spent, on average, over the entire Cold War; and the approximately 14 percent it spent at the peak of the emergency rearmament during the Korean War.³⁹

America allocated vast sums to defense in prior crises. The view that spending a significantly smaller share of GDP on defense now is absurd or impossible shows how complacent Americans have become in a world they can’t imagine falling apart.

During the Cold War, in fact, the United States often treated geopolitical shocks—like the outbreak of the Korean War and the Soviet invasion of Afghanistan—as opportunities to reinvest in defense. Washington could have done something similar after Russia’s invasion of Ukraine. But despite everything the Biden administration did well in February 2022 and after—arming Ukraine, expanding NATO, and rallying a broad international coalition—it failed to pair support for Kyiv with a major US rearmament program.⁴⁰

That decision was doubly unfortunate. It allowed critics to claim (somewhat misleadingly) that Ukraine aid was leeching capabilities from the US military.⁴¹ And it let the energy that this century’s greatest geopolitical crisis might have generated go to waste.

The politics of defense haven’t subsequently become any easier. The economics are also difficult, mostly because runaway entitlement spending—and an allergy to taxation—has created spiraling deficits that not even the United States can forever ignore.⁴² Yet it’s ironic to suggest that fiscal rectitude requires holding the line on defense—but not on the issues that are truly wrecking America’s national finances. It’s also irresponsible, because if America waits to fund defense until it has fixed the deficit, it will have waited too long.

If America doesn’t fix its defenses, it will ultimately pay the bill in lives, equipment, and influence lost and in the return of a world far less prosperous and secure than the one we know. The great lesson of the 20th century is that preserving global security is expensive. But it is far cheaper than rebuilding international peace and America’s national security once they have been shattered.

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