The time has come for the United States to build a collective defense pact in Asia. For decades, such a pact was neither possible nor necessary. Today, in the face of a growing threat from China, it is both viable and essential. American allies in the region are already investing in their own defenses and forging deeper military bonds. But without a robust commitment to collective defense, the Indo-Pacific is on a path to instability and conflict.
Tactical shifts aside, Beijing’s geopolitical aspirations for “the great rejuvenation of the Chinese nation” remain unchanged. China seeks to seize Taiwan, control the South China Sea, weaken U.S. alliances, and ultimately dominate the region. If it succeeds, the result would be a China-led order that relegates the United States to the rank of a diminished continental power: less prosperous, less secure, and unable to fully access or lead the world’s most important markets and technologies.
After decades of pouring resources into its armed forces, China could soon have the military strength to make that vision a reality. As CIA Director William Burns revealed in 2023, Chinese President Xi Jinping has instructed his military “to be ready by 2027 to invade Taiwan.” But as Burns went on to note, China’s leaders “have doubts about whether they could accomplish that invasion.” To sustain those doubts—concerning Taiwan but also other potential targets in the region—should be a top priority of U.S. foreign policy. That requires convincing Beijing that any attack would ultimately come at an unacceptable cost.
With that objective in mind, the United States has invested in advanced military capabilities and developed new operational concepts. It has moved more mobile and lethal military forces to strategic locations across Asia. Crucially, it has overhauled its security partnerships in the region. In past decades, Washington’s principal focus was to forge close bilateral ties. In recent years, by contrast, the United States has pursued a more networked approach that gives U.S. allies greater responsibilities and encourages closer ties not just with Washington but among the allies themselves. These changes are creating novel military and geopolitical challenges for Beijing, thereby reinforcing China’s doubts about the potential success of aggression.
The new, more multilateral approach marks a critical step toward stronger deterrence. But the defense initiatives it has produced remain too informal and rudimentary. In the face of continued Chinese military modernization, true deterrence requires the will and capability that only a collective defense arrangement can deliver. Such an alliance—call it the “Pacific Defense Pact”—would bind those countries that are currently most aligned and prepared to take on the China challenge together: Australia, Japan, the Philippines, and the United States. Additional members could join as conditions warrant.
Skeptics may argue that such an arrangement is infeasible with a Trump administration that appears to disavow the importance of the United States’ alliances. But the reality is that leaders in Washington and allied capitals are still working to deepen military cooperation in the Indo-Pacific despite economic and diplomatic tensions. As far as defense matters are concerned, there has been far more continuity than disruption to date. Provided the administration avoids debilitating economic measures targeting U.S. allies, the trends pointing the way toward collective defense in the region are likely to endure. And if the Trump administration ultimately lacks the vision and ambition to grasp this opportunity, defense establishments can and should still lay the foundations for future leaders.
TIMES HAVE CHANGED
This is not the first time Washington has confronted the question of how to design its security partnerships in Asia. After World War II, the United States crafted a network of alliances in the region, hoping to keep Soviet expansion at bay, entrench its own military presence—particularly in East Asia—and curb internecine tensions among its partners. This network, made up of separate security arrangements with Australia and New Zealand, Japan, the Philippines, South Korea, Taiwan, and Thailand, served its constituents well. It insulated large stretches of the Indo-Pacific from great-power conflict, setting the conditions for decades of remarkable economic growth. It also proved resilient, weathering the wars in Korea and Vietnam, successive waves of decolonization and democratization, and even the end of the Cold War itself.
Notably, the network never evolved beyond a set of disparate and almost exclusively bilateral alliances. In Europe, U.S. officials embraced collective defense: an attack on one ally would be treated as an attack on all. (Such was the logic behind the founding, in 1949, of NATO, the North Atlantic Treaty Organization.) In Asia, however, similar aspirations foundered. As John Foster Dulles, one of the architects of the U.S. postwar security order, wrote in these pages in 1952, shortly before becoming secretary of state: “It is not at this time practicable to draw a line which would bring all the free peoples of the Pacific and East Asia into a formal mutual security area.”
For their part, many Asian leaders preferred strong bilateral relationships with the United States over closer links with former adversaries or historical rivals. Some worried that a collective defense arrangement would draw them into a great-power clash between Washington and Moscow. Others doubted that any such institution could overcome the legacies of conflict and mutual distrust among their neighbors and bring together members that were far apart both geographically and in terms of security concerns. The only seeming exception, the Southeast Asia Treaty Organization, proved the point. Founded in 1954, SEATO was a motley alliance among Australia, France, New Zealand, Pakistan, the Philippines, Thailand, the United Kingdom, and the United States. It suffered from a lack of unity and quietly dissolved in 1977.
But times have changed. The conditions once preventing multilateral alignment in Asia are giving way to fresh calls for collective defense. Just before taking office last year, Japanese Prime Minister Shigeru Ishiba warned that “the absence of a collective self-defense system like NATO in Asia means that wars are likely to break out.” In fact, such a collective defense pact is now within reach. Three trends buttress this conclusion: a new strategic alignment centered on an advancing threat from China, a new convergence of security cooperation among U.S. allies, and the demand for a new reciprocity that gives the United States’ partners a larger role in keeping the peace.
COMMON CAUSE
China’s assertiveness throughout the Indo-Pacific is spreading a sense of insecurity, particularly as leaders in Beijing lean on the military as a central instrument in their revisionist aims. The dangerous and threatening activities of the People’s Liberation Army (PLA), combined with its rapidly growing capabilities, have prompted leaders across the region to adopt new defense strategies arrayed against what they perceive as a growing threat from China. New military investments and activities have followed suit.
Nowhere is this strategic reorientation more apparent than in Tokyo. Despite deep economic interdependence between China and Japan, ties between the two countries have been frail for decades, strained by historical animus, trade tensions, and territorial disputes. Relations have only worsened in recent years, as Beijing has leveraged its budding economic and military power to ramp up pressure on its neighbor. A new law, passed in 2021, allows China’s coast guard to use weapons against foreign ships sailing in what Beijing considers its sovereign waters. In the years since, Chinese incursions into the areas surrounding what Japan refers to as the Senkaku Islands—administered by Japan but also claimed by China, which refers to them as the Diaoyu Islands—have become more frequent, with greater numbers of larger and more heavily armed vessels. In March, Chinese coast guard ships entered the territorial waters around the islands and lingered for nearly 100 hours—the longest episode to date in a string of incidents that Japan’s top diplomat described as “clearly escalating.”
Tokyo is responding by loosening long-standing political and legal constraints on its armed forces. As early as 2013, the country’s first-ever publicly released national security strategy warned of China’s “rapidly expanded and intensified” activities around Japanese territories. Not long after, the Japanese government reinterpreted the country’s pacifist constitution, allowing its armed forces to work more closely with partner militaries. In recent years, it has embarked on a historic military buildup, pledging to double its military spending to roughly two percent of its gross domestic product. Tokyo has also moved beyond its erstwhile focus on defensive capabilities and now aims to acquire and deploy “counterstrike capabilities,” including hundreds of long-range Tomahawk missiles. These changes, as the political scientist and Japan expert Michael Green wrote in these pages in 2022, are establishing Tokyo as “the most important net exporter of security in the Indo-Pacific.”
The Philippines is undergoing a similar transformation. For decades, the Philippine armed forces battled insurgents in the southern reaches of the archipelago. Military investments and operations reflected that domestic focus. Today, the insurgency has weakened, but an external threat looms larger and larger: steady Chinese encroachment on Philippine maritime rights and sovereignty, primarily in the South China Sea. In the 2010s, Beijing pursued an unprecedented campaign of land reclamation and built military bases atop reefs and islets that are also claimed by the Philippines and other Southeast Asian states. China has cordoned off one of these atolls, Scarborough Shoal, denying access to Philippine fishing vessels. At another reef, Second Thomas Shoal, violent attacks by Chinese vessels have disrupted efforts to resupply Philippine military personnel. Chinese coast guard ships have even harassed vessels conducting energy exploration inside the Philippines’ exclusive economic zone.
In Europe, America embraced collective defense; in Asia, similar aspirations foundered.
The view from Manila has sharpened accordingly. Beginning under President Rodrigo Duterte in the late 2010s and accelerating under his successor, Ferdinand Marcos, Jr., the Philippine military has been undertaking an ambitious modernization effort. The government adopted a watershed defense strategy in 2024 to secure the country’s periphery with investments in additional combat aircraft, tougher cyberdefenses, and more unmanned assets for intelligence, surveillance, and reconnaissance. There is little doubt about what is driving the overhaul: the need to better monitor and confront China’s coercive activities.
In Canberra, a few thousand miles to the south, the rise of China was once considered benign and beneficial to Australian interests. A series of diplomatic and military incidents in the past decade, however, have convinced many that the opposite is true. Revelations of malign Chinese Communist Party influence in Australian elections and policymaking ignited a political firestorm. And after Australia’s government called for an independent investigation into the origins of the COVID-19 pandemic, China unleashed a barrage of tariffs and other restrictions on Australian exports.
In the South China Sea, Australian armed forces have suffered the same malign pattern of harassment by Chinese jets and warships. The PLA is also operating closer than ever to Australia’s shores. Earlier this year, Chinese naval vessels circumnavigated Australia and disrupted commercial air traffic with live-fire exercises in the Tasman Sea. And amid intense efforts by China to make security inroads with Papua New Guinea, the Solomon Islands, and other Pacific Island countries, Australia’s foreign minister said in 2024 that her country is now “in a state of permanent contest in the Pacific.”
Against this backdrop, Canberra, too, is revising its defense priorities from top to bottom. As recently as 2016, the government’s official view was that a foreign military attack on its territory was “no more than a remote prospect.” By 2024, its updated national defense strategy warned that, owing to the present realities in the Indo-Pacific, “there is no longer a ten-year window of strategic warning time for conflict.” Instead of preparing for a wide variety of contingencies around the world, including counterterrorism in the Middle East, the Australian Defence Force is gearing up to fend off major threats closer to home. Prime Minister Anthony Albanese has unveiled plans for record military spending, including major investments in stockpiles of critical munitions such as long-range fires, antiship missiles, and missiles for air defense. The reforms highlight a growing conviction that the country’s advantageous geography no longer offers sufficient protection against the PLA. The public shares that apprehension: according to the Lowy Institute, a leading Australian think tank, the share of Australians who believed China would become a military threat to their country nearly doubled from 2012 to 2022. It now stands above 70 percent.
QUAD GOALS
Japan, the Philippines, and Australia have not only come to recognize China as their primary and common threat; they also increasingly acknowledge that their fates are intertwined with the broader region. This is true even on issues as sensitive as Taiwan, once a taboo subject in the region: “A Taiwan emergency is a Japanese emergency,” former Japanese Prime Minister Shinzo Abe declared in 2021. “If something happens to Taiwan, inevitably we will be involved,” the Philippine military chief warned earlier this year.
The view that Chinese aggression would have massive consequences for countries throughout the Indo-Pacific has resulted in an unprecedented deepening of security partnerships among Australia, Japan, the Philippines, and other regional powers. Analysts have described defense cooperation between Australia and Japan in particular as taking on “alliance-like characteristics.” A new reciprocal access agreement allows the Australian and Japanese militaries to operate in each other’s countries. August 2023 marked the first-ever visit by Japanese F-35 fighter jets to northern Australia, followed only days later by the inaugural deployment of Australian F-35s for military exercises in Japan.
Japan is finalizing a similar access agreement with the Philippines, which has emerged in recent years as the largest recipient of Japanese security assistance. In February, defense leaders from the two countries announced a spate of measures for closer security cooperation. In what could be read only as a thinly veiled reference to China, the Philippine secretary of defense explained that Manila and Tokyo’s “common cause” was to resist “any unilateral attempt to reshape the global order.”
That newfound common cause has animated a series of overlapping, complementary initiatives—what, in 2024, U.S. Secretary of Defense Lloyd Austin called “the new convergence in the Indo-Pacific”—that build on the United States’ traditional focus on bilateral ties in the region. The Biden administration in particular worked to supplement the older “hub-and-spokes” model with what it envisioned as a “latticework” of relationships in Asia. The AUKUS partnership brought together Canberra, London, and Washington to help Australia build conventionally armed, nuclear-powered submarines. As members of the Indo-Pacific Quad, Australia, India, Japan, and the United States joined efforts to provide maritime domain awareness throughout the region. American officials also stepped up trilateral security cooperation with Japan and South Korea.
Among the many partners involved in these efforts, Canberra, Manila, and Tokyo frequently stand out as common denominators. At a meeting of their leaders in 2024, the Japanese, Philippine, and U.S. governments expressed “serious concerns” about China’s “dangerous and aggressive behavior” and announced initiatives on infrastructure investment and technology cooperation, among other measures. Later that year, Australian, Japanese, and U.S. defense leaders unveiled another set of cooperative activities, including three-way military exercises and advanced defense industrial cooperation. Perhaps most promising of all is a new grouping that brings together all four of these parties—Australia, Japan, the Philippines, and the United States. Known informally as “the Squad” (to distinguish it from the Quad), the group conducts regular naval, maritime, and air force exercises in the South China Sea. It also plans to strengthen information sharing and work together to modernize the Philippine military.
A GOOD START
The new convergence in the Indo-Pacific represents a profound development in the security architecture of the region. But it is best viewed as an incomplete evolution—an important period of transition rather than an optimal end state. The shortcomings are significant. There are no mutual defense obligations between U.S. allies, only with the United States. There is no central headquarters to plan and conduct multilateral operations. And the unofficial nature of these groupings means that there is no regular drumbeat of planning among political and military staffs. Coordination is occurring, but only intermittently. As a result, it rarely receives the necessary urgency, attention, and resources.
A collective defense pact would deliver where the current mechanisms fall short. Getting there would not require a panregional security organization such as NATO, which grew from 12 original members to over 30. Instead, the logical starting point for Washington is to form a pact with the three partners that are most strategically aligned and have the fastest-growing and most robust combined military cooperation: Australia, Japan, and the Philippines.
Additional members could join later, circumstances allowing. As an advanced and stalwart ally in East Asia, South Korea would be an obvious candidate, and its contributions could be quite significant. But Seoul would have to decide whether it was willing to focus its defense forces more on China, partner more closely with Japan, and support a broader regional orientation for its own military and the tens of thousands of U.S. troops stationed on the peninsula. New Zealand would be another prospective partner, especially since it is already part of the Five Eyes intelligence-sharing group alongside Australia, Canada, the United Kingdom, and the United States. But although New Zealand has recently shown greater willingness to challenge China and align more closely with the United States, it might not yet be prepared to enter a formal collective defense pact.
Critical U.S. partners such as India and Singapore would not be expected to join at the outset but could still participate in certain activities as observers or in some other nonmember capacity, as is common in regional groupings. The inclusion of Taiwan would not be possible or advisable under current U.S. policy, nor would it be acceptable to the other members of the pact. As for the United States’ European allies, they are neither politically nor militarily ready to join as full members right now, but that option could be considered in the future, under different circumstances. Larger defense budgets in Europe could produce militaries with more global reach, provided the continent itself is secure and at peace.
Given the urgency of the China challenge, the United States cannot afford to wait for a perfect alignment among all its partners. There is already a core group in place and room to consider additional members in the future. Preparations should begin now. Given that alliances with the United States already exist, a first-order task is to establish mutual obligations among Australia, Japan, and the Philippines themselves. This will demand skillful leadership and intense negotiations, but the benefits of stronger deterrence and greater security should outweigh the risks of closer alignment. Besides, for Australia and Japan in particular, the practical differences between today’s defense partnership and one of mutual defense are relatively small and shrinking by the day.
From an operational perspective, collective defense could build on existing cooperative projects, including in the areas of intelligence sharing, maritime domain awareness, combined training and exercises, and command and control. One such project is the Bilateral Intelligence Analysis Cell, a new U.S.-Japanese effort at Yokota Air Base that monitors Chinese activity in the East China Sea. Japan and the United States could share the cell’s intelligence with Australia and the Philippines, which could in turn contribute personnel at the air base and provide data from their own unmanned surface and aerial platforms. Likewise, the recently inaugurated U.S.-Philippine Combined Coordination Center near Manila could include Australia and Japan, providing similar functions in the South China Sea.
A collective defense pact would deliver where current cooperation falls short.
The U.S. military has major operating bases in Japan, access to locations in the Philippines, and regular rotations of U.S. troops throughout Australia. With sufficient legal underpinning—including reciprocal access agreements among the three Asian allies— each of these arrangements could be expanded to include forces from the other members. In fact, there are already plans to integrate Japanese forces into U.S. initiatives in Australia.
The four members could also invest in shared military facilities. Major bilateral and trilateral military exercises involving different combinations of the partners could include all four. Together, they could more readily pre-position weapons to ensure sufficient stockpiles in the event of conflict, further strengthening deterrence. Establishing a headquarters for the Pacific Defense Pact and mechanisms for command and control will be essential. Japan could serve as one potential location. In July 2024, the United States announced its intent to upgrade the U.S. military command in Japan to plan and direct more missions in the region with its Japanese counterpart. As new facilities and communications links are established to support this effort, U.S. and Japanese officials should ensure that it will be possible to include military commanders and personnel from Australia and the Philippines. Alternative locations for the headquarters could be considered in Australia or at U.S. Indo-Pacific Command in Hawaii.
The four countries should establish a series of working groups to negotiate the full range of policy and legal issues associated with more integrated planning and operations. Military and civilian staff from defense and foreign ministries could work together to develop proposals for governance and decision-making processes, including personnel structures and consultation mechanisms that form the engine rooms of day-to-day alliance management. This breadth of tasks only underscores the need to start consultations as soon as possible.
ALL FOR ONE
In addition to deepening their collective cooperation with one another, U.S. allies will also need to rebalance their bilateral security partnerships with Washington. In their current form, those partnerships reflect the asymmetries of a different era, when American military primacy appeared uncontested and immutable. Bilateral treaties in the region were restricted in scope to specific local geographies, and the contributions of allied militaries were limited by design. In essence, the United States promised protection in exchange for military access and political-economic comity in Asia but without demanding fully reciprocal protection for itself.
This framework was sustainable—both strategically and politically—as long as the U.S. military retained its dominance in the region, the threat from China was confined, and the potential contributions of U.S. allies were limited to their own self-defense. None of these conditions holds true today. The PLA now poses serious challenges to the U.S. military and the American homeland. And U.S. allies in Asia are now among the wealthiest and most advanced countries in the world, capable of playing a significant role in both deterrence and warfighting. To adapt to this new reality, U.S. alliances need to build on a foundation not of asymmetry but of reciprocity.
Domestic politics in the United States also makes greater reciprocity necessary. Although most Americans support military ties in principle, increasing numbers would like to see U.S. allies contribute more in practice. U.S. President Donald Trump has focused in particular on the notion that allies need to pay their “fair share,” casting doubts on whether the United States would defend NATO members that failed to meet certain levels of military spending. U.S. allies do need to spend more on defense—but reciprocity should extend far beyond bigger military budgets.
Beijing will draw from its playbook of disinformation and economic coercion.
U.S. allies will also need to commit to greater degrees of mutual obligation with the United States. Washington’s security treaty with Tokyo, for instance, is bound only to “the territories under the administration of Japan.” The resulting imbalance is on display at every major bilateral summit, where U.S. leaders reaffirm their commitment to defend Japan and Japanese leaders stay silent on whether their forces would assist the U.S. military elsewhere. Instead, U.S. allies should commit to supporting the United States both in crises throughout the region and in defending the U.S. homeland.
This new reciprocity would further enable collective defense. The upshot of more mutual obligation would be that U.S. allies could take on new roles and missions in crises and conflicts, especially when combined with recent investments in their own militaries. This would, in turn, open new pathways for cooperation that do not exist today in sufficient form: members of the pact could draft combined military plans, more effectively target their defense spending toward specialized and complementary capabilities, and rehearse and improve together through tailored military exercises and operations. These measures would fortify the collective power and deterrence of the United States’ alliances far beyond what is possible under today’s informal mechanisms.
Greater reciprocity should also entail greater clarity on what military strategists refer to as “access, basing, and overflight”—that is, the ability of the U.S. military to operate in and around allied territory. Given the vast distances involved, forward-deployed U.S. forces are essential to ensuring rapid response times and sustaining the military during a contingency. More certainty surrounding U.S. military access would strengthen deterrence in the western Pacific by ensuring that the United States would have the right forces and capabilities ready to fight in the right places. More assured access would also lead to greater infrastructure investments and the deployment of more advanced capabilities, which further enhance the potential utility of various locations. While U.S. allies should not be expected to give the U.S. military a blank check, a robust Pacific Defense Pact will require more flexible and assured access for U.S. forces.
THE CORE FOUR
Collective defense touches on matters of sovereignty and treaty obligations, deeply political issues that require intense negotiations and deft diplomacy. This will be all the more challenging if the Trump administration moves forward with punishing tariffs or other measures that strain Washington’s alliances in the region. But even amid tense diplomatic relations, defense and military establishments can continue laying the foundations for collective defense. Short of a severe break in ties, the four partners should work as best they can to silo security cooperation from economic and diplomatic disagreements. The stakes are simply too high to do otherwise. It is also worth underscoring that the demand for more reciprocal relationships has become a political and strategic imperative that spans the partisan divide in Washington.
The evidence to date is that the United States and its Indo-Pacific allies are managing to deepen defense cooperation despite political and economic headwinds. This is largely owing to the mounting threat from China, the continued demand for a U.S. military presence in the region, and the growing trend of intra-Asian security cooperation. To be sure, the Trump administration may be too divided, distracted, or confrontational to play the winning hand it has been dealt. In that case, many of the building blocks can still be put in place for a future administration. Given the number of tasks ahead, a pact might not be finalized until the next U.S. administration anyway.
For their part, leaders in Canberra, Manila, and Tokyo will need to win the support of their respective domestic publics. Beyond strategic arguments about deterrence and national security, the United States can support these conversations by highlighting the potential benefits to its allies’ domestic constituencies. These could include technology sharing, infrastructure investments, and improved disaster response. In the United States, skeptics can be assured that a defense pact in the Pacific would entail no obligations for the U.S. military beyond what is already in place—but that it would reduce threats to the U.S. homeland and to U.S. troops.
Given the historic significance of such an arrangement, Washington should also be prepared to manage reactions and concerns from others in the Indo-Pacific. U.S. officials can underscore that a Pacific Defense Pact would be but one of several components of its approach to the region. In both rhetoric and practice, Washington should remain committed to a network of overlapping and complementary institutions, including the Indo-Pacific Quad, the Association of Southeast Asian Nations, and trilateral cooperation with Japan and South Korea. The publicly stated objective of the pact should be the pursuit of a “free and open Indo-Pacific,” a goal shared by nearly every country in the region.
Moreover, the pact should remain focused on defense rather than subsuming or taking on the economic and diplomatic roles of other important institutions. Indeed, the pact will be most successful if complemented by a robust regional trade agenda, active diplomatic efforts, and effective foreign assistance programs.
Protests from Beijing will no doubt be as loud as they are predictable. China has long accused the United States of “Cold War thinking” and “bloc politics.” PLA officials have already warned that current U.S. efforts to bring American security partners closer together are “tying the region’s countries to the U.S. war chariot.” These refrains will feature prominently in China’s reaction precisely because a stronger coalition could stymie Beijing’s revisionist ambitions. To push back and make potential members think twice about a new pact, Beijing will likely draw from its traditional playbook of disinformation and economic coercion. With that in mind, the United States should help its allies prepare for China’s efforts to scuttle a collective defense arrangement in Asia.
None of this will be easy. But neither was the great progress that Washington’s allies have already made, not only in acknowledging the threat from China but also in taking unprecedented steps to invest in their own militaries, build ties with their neighbors, and double down on their alliances with the United States. In fact, in recent years, Australia, Japan, and the Philippines have already made moves on defense and security matters that were previously deemed implausible. The conditions are now set for strong leadership to transform a collective defense pact in Asia from something once unimaginable into a defining feature of the region’s future peace and prosperity.