Japan, the War in Ukraine, and Japan–Europe Relations: A G7–NATO Alignment Perspective

Japan has emerged as Asia’s most resolute backer of Ukraine in its struggle against Russia’s brutal and unprovoked aggression. This support is not incidental. It reflects Tokyo’s deliberate effort to reposition itself as a frontline defender of the post–Cold War order—a posture it has pursued through deepening ties with European partners in both security and defense domains. With USD 9 billion in total assistance, Japan now ranks as the fifth-largest international donor to Ukraine, behind only the United States, Germany, the United Kingdom, and France.¹ More striking still, among the 51 states participating in the Ukraine Defense Contact Group, Japan stands alone as the only country outside the Euro-Atlantic area to sign the Ukraine Compact—an agreement formalized in July 2024 and notable for its symbolism and strategic intent.

Japan’s support is not merely financial. It is political, diplomatic, and increasingly strategic. Through the Group of Seven (G7) and its intensifying partnership with NATO, Japan has cast its lot with the liberal democratic powers of the West. This alignment raises critical questions: What motivates Japan to shoulder burdens in a war thousands of miles from its shores? Why does Tokyo’s support matter in the evolving global order? And in what ways have Japan–Europe relations enabled or amplified Japan’s role in Ukraine’s defense?

To answer these questions, this article employs a “what–why–how” framework, analyzing Japan’s objectives, rationale, and operational approach through the lens of its engagement with Europe—particularly via G7 diplomacy and institutional coordination with NATO.²

Scholars have approached Japan’s support for Ukraine from several angles. One school emphasizes the tension between continuity and change in Japanese foreign policy. For decades, Tokyo hewed closely to constitutional pacifism while quietly expanding its global diplomatic footprint. The invasion of Ukraine by a permanent member of the UN Security Council—brazenly violating the UN Charter—has forced a reckoning. Japan does not frame the war as a clash between democracy and authoritarianism, as Washington often does. Instead, Japanese leaders have cast it as a fundamental assault on international norms—namely, sovereignty, territorial integrity, and the prohibition against the use of force to alter borders.³

Other analysts highlight Tokyo’s evolving posture toward Moscow. For much of the post–Cold War period, Japan pursued a policy of cautious engagement with Russia, motivated by a desire to resolve the Northern Territories dispute and to prevent Russia from falling deeper into China’s strategic orbit.⁴ The war in Ukraine upended that calculus. Since 2022, Japan has pivoted decisively, designating Russia as a “strong security concern” and joining Western sanctions and diplomatic rebukes—actions unthinkable a decade ago.⁵

A third, narrower perspective centers on bilateral Japan–Ukraine ties. While there is a modest body of literature tracing Japan’s political, economic, and humanitarian assistance to Ukraine, this analysis tends to treat the relationship in isolation. It overlooks the broader geopolitical significance of Japan’s Ukraine policy—particularly its implications for Japan’s security alignment with Europe and its emerging role as a normative power capable of shaping global responses to territorial aggression.

Russia’s full-scale invasion of Ukraine in 2022 did more than redraw the strategic map of Europe—it coincided with, and catalyzed, Japan’s intensifying pursuit of security and defense partnerships with Europe.⁶ Long before Russian armor crossed into Donbas, Tokyo had already begun recalibrating its foreign policy, seeking new alignments with the European Union, NATO, and key European states.⁷ The aim was clear: to diversify its strategic dependencies and forge a shared transregional understanding of the global nature of the challenge posed by China.

While the COVID-19 pandemic had already chipped away at European illusions about Beijing, it was Russia’s war—tacitly endorsed and economically sustained by China—that hardened European resolve. For Japanese strategists, this confluence of events reinforced the imperative to knit together like-minded democracies across continents. The Ukraine war became the crucible in which Japan–Europe defense cooperation matured from aspirational to operational.

Yet, much of the existing literature remains confined to Japan’s early material support for Ukraine—its sanctions, aid packages, and refugee resettlement efforts. These accounts miss the deeper transformation: Japan’s support for Ukraine is not an isolated gesture of solidarity but a logical extension of its broader strategic pivot westward. It marks a deliberate integration of Japan into Europe’s evolving security architecture, not merely as a partner, but increasingly as a stakeholder.

One common analytical misstep is the tendency to treat Japan’s engagement with the G7 and NATO as separate or loosely related tracks. This compartmentalization obscures the profound and, in many respects, unprecedented convergence between the two institutions. The G7, dominated by European powers—France, Germany, Italy, and the United Kingdom, with the EU as an observer—overlaps almost entirely with NATO membership, which includes the United States and Canada. Japan’s involvement with both should not be seen as parallel diplomacy, but rather as a unified axis of engagement, leveraging its position in the G7 to interface with NATO’s strategic ecosystem.

This article seeks to fill the analytical gap by reframing Japan’s Ukraine policy within the broader context of its deepening alignment with Europe. It argues that Japan’s support for Ukraine is not just a response to Russian aggression but a strategic recalibration with implications far beyond Eastern Europe. It is a signal—to allies and adversaries alike—that Japan intends to shape, not merely observe, the future contours of global order.

The article proceeds as follows. The next section offers a concise historical overview of Japan–Ukraine political relations to establish a baseline. The third section identifies key strategic parallels between the Ukraine war and Japan’s own regional security concerns, thereby clarifying Tokyo’s motivations. The fourth section explores why Japan’s support for Ukraine matters—not only for the defense of Europe but for the stability of international norms writ large. The fifth section analyzes the operational mechanisms of Japan’s coordination with Europe, focusing on its multilateral work through the G7 and NATO. The article concludes by assessing the continued utility of the “what–why–how” framework and draws forward-looking implications for Japan–Europe relations in the context of a second Trump administration.

Japan–Ukraine Bilateral Relationship

Japan recognized Ukraine’s independence swiftly, establishing diplomatic relations in 1992. From the late 1990s onward, Tokyo extended technical and financial aid to Kyiv as part of its broader assistance to post-Soviet states.⁸ The 2011 Great East Japan Earthquake provided an unexpected catalyst for closer bilateral ties. Japan turned to Ukraine’s Chernobyl disaster experience for insight into nuclear disaster management.⁹ This cooperation evolved into joint technical monitoring of both the Chernobyl and Fukushima nuclear sites, using Japanese satellites launched aboard Ukrainian rockets.¹⁰ Yet despite these practical collaborations, the political relationship lacked institutional depth. It was not until 2015 that a sitting Japanese prime minister—Shinzō Abe—set foot in Ukraine.

This diplomatic reticence was not accidental. Russia’s 2014 annexation of Crimea coincided with Japan’s own high-stakes effort to normalize relations with Moscow. Tokyo’s strategic calculus at the time centered on two objectives: to resolve the decades-long Northern Territories dispute and to prevent a diplomatically isolated Russia from pivoting further into China’s geopolitical orbit.¹¹ In this balancing act, Ukraine became collateral. Japan issued only a tepid response to the annexation, stating it did not recognize Crimea as part of Russia, suspending visa liberalization talks, and halting negotiations on new agreements.¹² There were no sanctions of consequence. The preference was clear—preserve the diplomatic window with Moscow, even at the cost of principle.

Nonetheless, Japan did draw a red line. It maintained that Russia, a permanent member of the United Nations Security Council, had violated international law by undermining the unity, sovereignty, and territorial integrity of a fellow UN member. Tokyo’s official stance condemned Russia’s attempt to unilaterally alter the status quo by force—a transgression Japan would not tolerate, whether in Eastern Europe or the Indo-Pacific.

Prime Minister Abe’s 2015 visit to Kyiv marked a turning point. While the gesture was largely symbolic, it laid the groundwork for emerging defense cooperation, including a cyber consultation in 2016 and a defense memorandum and exchange in 2018.¹³ These initiatives remained modest—until Russia launched its full-scale invasion in February 2022. In the opening days of the war, Prime Minister Fumio Kishida condemned the Russian assault, stating that it “shakes the foundation of the international order that never tolerates unilateral change of the status quo by force.”¹⁴

Kishida’s timing was strategic. With Japan poised to assume the G7 presidency in 2023, he recognized an opportunity to showcase Japan’s leadership beyond Asia. Tokyo began translating rhetoric into policy. In March 2023, Japan and Ukraine elevated their diplomatic ties to a “Special Global Partnership.” A year later, Japan became the first nation outside the Euro-Atlantic area to sign a bilateral agreement committing to Ukraine’s defense—a diplomatic milestone that repositioned Tokyo as a pivotal actor in the global response to Russian aggression.¹⁵

What Is the Purpose of Japan’s Support for Ukraine?

At the 2022 Shangri-La Dialogue, Prime Minister Fumio Kishida issued a stark warning: “Ukraine today may be East Asia tomorrow.” This was not a rhetorical flourish. It was a calculated statement of strategic doctrine. For Tokyo, the Russian war against Ukraine is not a distant European crisis—it is a rehearsal for the Indo-Pacific. Japan discerns three ominous parallels: the normalization of nuclear blackmail, the erosion of territorial integrity, and the imperative of defense self-reliance.

First, nuclear coercion.

Russia has wielded its nuclear arsenal not as a deterrent but as a shield behind which it wages conventional war with impunity. Moscow has paid no meaningful price for its nuclear saber-rattling.¹⁶ For Japan, this sets a dangerous precedent. Tokyo sits in a neighborhood ringed by three nuclear powers—Russia, China, and North Korea—all of which have grown bolder in recent years. Pyongyang, undeterred by international condemnation, amended its constitution in September 2023 to declare its intention to “develop nuclear weapons to a higher level.”¹⁷ Beijing, meanwhile, is expanding its strategic forces at breakneck speed, with an estimated 600 operational warheads as of mid-2024.¹⁸ And Russia remains the world’s second-largest nuclear power after the United States.¹⁹

Japan relies on the American nuclear umbrella. But extended deterrence is only as credible as the will behind it. The failure of the 1994 Budapest Memorandum—which offered Ukraine security assurances in exchange for denuclearization—has cast a long shadow. Kyiv gave up its nuclear weapons. In return, it received promises. Those promises proved worthless. The lesson is not lost on Tokyo. With doubts now growing about Washington’s commitment to allies under the second Trump administration, Japan must hedge against strategic abandonment.²⁰

Second, territorial integrity.

The United Nations Charter enshrines the principle of sovereign equality and prohibits the use of force to alter borders. Yet international law, in the absence of power, is just parchment. Japan understands this acutely. It remains embroiled in unresolved territorial disputes, most notably with Russia over the Northern Territories—seized by Soviet forces in the waning days of World War II. Eighty years later, no peace treaty exists.

Japan sees Ukraine’s predicament mirrored in Taiwan’s. While Ukraine is universally recognized as a sovereign state, Taiwan occupies a legal and diplomatic gray zone. Only a handful of nations recognize its statehood. China, in defiance of historical fact, claims Taiwan as its own.²¹ Yet Taiwan’s Ministry of Foreign Affairs is unambiguous:

“Taiwan has never been part of the People’s Republic of China (PRC). This is an objective fact and an internationally recognized status quo . . . Taiwan’s sovereignty belongs to the Taiwanese people, and only Taiwanese themselves can decide Taiwan’s future. . . . Taiwan will neither provoke nor bow to pressure from China. The government will continue to staunchly defend Taiwan’s territorial integrity, national sovereignty, and national security.”²²

Beijing, however, does not rule out force.²³ Should war erupt over Taiwan, estimates suggest USD 2.6 trillion could vanish from the global economy—an order of magnitude more devastating than the economic fallout of Ukraine.²⁴

The message from Tokyo is clear: territorial conquest, nuclear coercion, and gray-zone warfare must not be allowed to succeed—whether in Europe or in Asia. A failure to respond decisively in one theater invites catastrophe in the other.

Third, defense self-reliance.

The third and most sobering parallel Japan draws from the Ukraine conflict is the imperative of defense self-reliance. In a world absent of a global enforcer—a world governed by power rather than principle—realists have long argued that survival depends on the capacity to defend oneself.²⁵ Japan, tethered to a longstanding alliance with the United States, now finds itself recalibrating that assumption. The American umbrella remains open, but its fabric has begun to fray.

Tokyo’s recognition of this strategic reality is not new, but it has grown sharper and more urgent. Japan’s first National Security Strategy, adopted in 2013, articulated a three-pronged vision: to bolster indigenous defense capabilities, reinforce the US–Japan alliance, and expand partnerships with other like-minded democracies. The 2022 revision deepened this approach, explicitly embracing a doctrine of proactive deterrence. The new posture includes doubling defense spending, acquiring counterstrike capabilities, and strengthening military-industrial cooperation with states across Europe and the Indo-Pacific.

The war in Ukraine has become a case study in modern defense resilience. Ukrainian forces, far outgunned and outnumbered, have withstood the assault of a major nuclear power by relying on grit, improvisation, and external support. That lesson is not lost on Japanese strategists. If Ukraine—without formal alliance guarantees—can impose costs on Moscow, then Japan must ensure it can do the same to any regional aggressor. The principle is not mere imitation; it is adaptation. Tokyo understands that, in the event of a Taiwan contingency or a crisis in the East China Sea, the first hours will determine whether deterrence holds or collapses. Preparedness cannot be subcontracted.

Japanese public opinion has shifted in tandem with this new strategic clarity. Two years into the war, polling revealed sustained public support for Ukraine, including the resettlement of Ukrainian refugees.²⁶ This reflects not only empathy, but a broader recognition that Japan’s national security is bound to the global defense of sovereignty and law.

In September 2024, Shigeru Ishiba assumed the premiership in a moment of mounting geopolitical uncertainty. At the third anniversary of the Ukraine war, Ishiba addressed a virtual G7 summit—one notably clouded by American disengagement. The new US president had shown little interest in sustaining Ukraine’s fight. Nonetheless, Ishiba delivered a message with unmistakable resolve: the international community must not absorb the wrong lessons from Ukraine—that nuclear intimidation works, or that borders can be redrawn by force without consequence.²⁷ The wrong lessons are that countries can get away with nuclear bullying and invading another country’s territory.

Japan’s support for Ukraine is thus not a distant act of charity—it is a proximate act of self-preservation. It is aimed squarely at China. The message is calibrated and strategic: any attempt by Beijing to replicate Moscow’s adventurism in the Indo-Pacific will provoke a coordinated response. The stakes extend well beyond the defense of Ukraine. They include the fate of Taiwan, the credibility of US alliances, and Japan’s own survival as a sovereign nation in a rapidly hardening global order.

Why Does Japan’s Support for Ukraine Matter?

Japan’s support for Ukraine matters not only because of what it represents, but because of what it prevents. It reinforces two pillars of the current international order: the indivisibility of security between Europe and Asia, and the sanctity of territorial integrity under international law. Both are under direct assault.

Japan has long asserted that the war in Ukraine is not a regional dispute but a global inflection point.²⁸ This is not a diplomatic abstraction. It is a strategic conviction grounded in geography, history, and power politics. For years, Tokyo attempted to coax Moscow out of Beijing’s orbit—an effort now thoroughly overtaken by events. Russia and China have deepened their military, economic, and diplomatic partnership, with Beijing playing the role of economic enabler, shielding Moscow from the full weight of Western sanctions. Chinese state-owned enterprises continue to supply Russia with components vital to its war machine, while providing financial and trade lifelines through yuan-based settlements and gray-market logistics.

Beijing’s support is transactional but strategic. Its goal is to ensure the survival—and ideally the success—of a fellow authoritarian regime hostile to the West and sympathetic to Chinese ambitions. The longer Russia bleeds NATO and fractures transatlantic unity, the greater the strategic space for China to act in the Indo-Pacific.²⁹

This alignment is not merely rhetorical. China and Russia have expanded joint naval exercises and long-range bomber patrols—often in Japan’s maritime backyard.³⁰ These operations are not confidence-building measures. They are rehearsals, intended to demonstrate that both states can operate in tandem against shared adversaries. North Korea, too, has entered this axis of autocracy. In 2022, it was one of just six states to vote against a UN resolution demanding Russia halt its aggression.³¹ Since then, Pyongyang has reportedly dispatched labor, materiel, and troops to support Moscow’s war effort.³² The Russia–North Korea strategic partnership now functions as a visible bridge between European and Asian theaters.

For Tokyo, these developments obliterate any lingering notion of strategic compartmentalization. The Indo-Pacific and the Euro-Atlantic are no longer discrete arenas. They are two fronts in a single, systemic struggle. That is why Japan’s support for Ukraine must be viewed not as an act of altruism, but as a strategic imperative. If non-European states like China and North Korea are backing Russia, then non-European democracies—including Japan—must do the same for Ukraine. Otherwise, deterrence will collapse, first in Europe, then in Asia.

The second reason Japan’s support matters lies in its defense of first principles. If Russia’s invasion succeeds—if borders can be redrawn by force and treaties shredded with impunity—then the international order becomes a carcass for revisionist powers to pick apart. The principle of territorial integrity, as enshrined in Article 2(4) of the UN Charter, is not self-enforcing. It requires collective will, consistent action, and credible penalties.

That is precisely what the G7, with Japan assuming a pivotal leadership role in 2023, set out to achieve. Sanctions remain among the most potent instruments available to democracies short of armed conflict. When wielded with coordination and resolve, they can impose real costs—not only on a belligerent’s military-industrial base, but on its long-term capacity to wage geopolitical revisionism. The G7’s response to Russian aggression has been both comprehensive and strategic, targeting the architecture that enables the Kremlin’s war effort.

The measures include:³³

1. Establishing an Enforcement Coordination Mechanism to detect, prevent, and punish sanctions evasion and circumvention;

2. Cutting off Russia’s access to advanced materials, technologies, and dual-use industrial equipment sourced from within G7 jurisdictions;

3. Imposing export bans and enforcing a price cap on seaborne Russian-origin crude oil and refined petroleum products, designed to squeeze revenue without triggering global supply shocks;

4. Severing one of Moscow’s less-publicized but lucrative revenue streams by restricting the export of Russian diamonds;

5. Targeting Russian financial institutions that serve as conduits for sanctions evasion, money laundering, or proxy financing; and

6. Pursuing and penalizing individuals implicated in war crimes, human rights violations, and systemic abuses in occupied territories.

These actions, while not decisive alone, form part of a long-term strategy to degrade Russia’s capacity to sustain its war and to raise the cost of aggression globally. But Japan’s contributions extend beyond coercive tools. Tokyo has also led on the economic reconstruction front. In early 2024, it hosted the Japan–Ukraine Conference for the Promotion of Economic Growth and Reconstruction, an effort to galvanize public-private partnerships across sectors. Germany followed suit, and Italy is set to host a third such event in 2025.³⁴

Japan’s reconstruction initiative signals its commitment not only to Ukraine’s survival, but to its postwar revival. This is strategic statecraft—ensuring that Ukraine emerges not as a broken ward of the West, but as a functioning, sovereign democracy embedded in the global economy. Tokyo understands that the restoration of Ukraine is part of the broader fight to uphold a rules-based order that prevents conflict in Asia before it begins.

How Japan–Europe Cooperation Supported Japan’s Efforts in Ukraine?

Japan has supported Ukraine through both bilateral and multilateral means. But its most consequential contributions have emerged through its strategic coordination with Europe—principally via the G7 and NATO. While other platforms such as the Ukraine Defense Contact Group and the Ukraine Compact serve Ukraine-specific functions, the G7 and NATO have been instrumental in elevating Japan’s global diplomatic profile and embedding its actions within a larger coalition of democratic powers. Japan’s 20-year engagement in Afghanistan stands as precedent; its role in Ukraine reaffirms the trajectory from a reluctant power to a committed actor in global security.³⁵

Despite being the only non-European and non-NATO member of the G7, Japan did not hesitate when war returned to the European continent. It acted swiftly and in solidarity—aligning its policy, messaging, and aid commitments with the Euro-Atlantic bloc through the G7 and NATO frameworks. This was not symbolic diplomacy. It was strategic alignment.

The G7, once primarily an economic coordination body, has evolved into a forum where security and strategic issues are addressed with increasing regularity and candor. For Japan, its G7 membership is not a token of prestige—it is a platform to shape policy at the highest levels. While the G20 may serve as the global economic forum of record,³⁶ the G7 remains the exclusive club where democratic powers speak freely and act decisively. In this arena, Japan’s voice carries growing weight.

Recent years have witnessed an unprecedented convergence between the G7 and NATO. During the chaotic withdrawal from Afghanistan, NATO’s secretary general joined G7 virtual sessions to coordinate evacuations.³⁷ This alignment only deepened following Russia’s invasion of Ukraine. On 24 March 2022, NATO hosted an extraordinary summit in Brussels. That same day, it convened the G7 heads of state—with NATO leadership participating in both forums.³⁸ Just months later, the G7 summit immediately followed NATO’s, symbolizing the tight strategic synchronization now defining these two bodies.

There are two structural advantages to this G7–NATO alignment. First, the G7’s informal and less-scripted nature allows for frank exchanges—a flexibility not always present in NATO’s protocol-bound sessions. Second, while NATO is necessarily focused on military defense, the G7 spans broader domains—economic resilience, energy and food security, sanctions coordination, and financial stabilization.³⁹ As the war in Ukraine expanded beyond the battlefield to become a test of global endurance, the G7 proved essential in confronting these geoeconomic dimensions.

It was against this backdrop that Japan assumed the G7 presidency in 2023. On the margins of the NATO Summit in Vilnius that July, Japan played a leading role in drafting and finalizing the Joint Declaration of Support for Ukraine. That declaration established three principal commitments:⁴⁰

1. Delivering sustained assistance to Ukraine across security, defense industrial, intelligence, financial, and technical domains;

2. Escalating costs on Russia through sanctions, export controls, asset freezes, and legal accountability for war crimes; and

3. Supporting Ukraine’s internal reform agenda—including anticorruption measures, judicial modernization, and defense-sector restructuring.

The declaration became the basis for bilateral security agreements between Ukraine and each G7 state. In turn, those agreements formed the legal and political scaffolding for the Ukraine Compact, signed in July 2024 on the sidelines of the NATO Summit in Washington.⁴¹ These mechanisms—born from the hard lessons of the failed 1994 Budapest Memorandum—are not formal NATO commitments, nor are they legally binding treaties. But they constitute an incremental and deliberate process toward establishing long-term security guarantees for Ukraine.⁴²

In parallel with its G7 leadership, Japan has also deepened its engagement with NATO—particularly through the NATO–IP4 format, also referred to as the Asia-Pacific Four (AP4). This grouping—comprising Japan, Australia, New Zealand, and South Korea—represents NATO’s closest Indo-Pacific partners. Each has an individually tailored cooperation program with the alliance, and NATO’s 2022 Strategic Concept explicitly recognizes the indivisibility of Euro-Atlantic and Indo-Pacific security.

On 29 June 2022 in Madrid, Japan assumed a leading role at the inaugural Leaders’ Meeting of the AP4 convened just prior to the NATO Summit. The agenda was unambiguous: to assess the war in Ukraine not as a distant European conflict, but as a harbinger of systemic instability reverberating across the Indo-Pacific. For Japan, this was not an exercise in diplomatic pageantry. It was strategic positioning—Tokyo asserting itself as the Indo-Pacific’s voice within the Euro-Atlantic security dialogue.

All four AP4 states participate in NATO’s Comprehensive Assistance Package for Ukraine, but it was at Madrid where they spoke with unusual clarity. The leaders reached consensus: responsibility for the war rests squarely with Russia.⁴³ That political convergence marked the formalization of what has since become a regularized framework for strategic engagement. Since 2022, the AP4 have convened at every relevant echelon: summits, foreign ministerials, defense chiefs, and most recently, ministerial-level defense coordination.⁴⁴ This is no longer an ad hoc gathering; it is an emergent architecture of Indo-Pacific alignment with NATO.

The tangible output of these engagements is already visible. The AP4, under NATO coordination, have launched four flagship projects in support of Ukraine: military healthcare support, cyber defense, counterdisinformation operations, and the application of artificial intelligence to defense resilience.⁴⁵ These are not peripheral initiatives—they strike at the heart of modern warfare and the instruments of hybrid aggression.

Although Ukraine is but one dimension of the NATO–AP4 framework, Japan’s leadership has been decisive. It was the first among the four to sign a bilateral security agreement with Ukraine and the first non–Euro-Atlantic country to join the Ukraine Compact. These are not symbolic gestures; they are unmistakable markers of Japan’s strategic intent: to transition from observer to architect in the shaping of a rules-based order—one that extends from the Baltic to the South China Sea.

Conclusion

This article employed a “what–why–how” framework to interrogate Japan’s motivations, logic, and operational approach in its support for Ukraine—viewed through the prism of Japan–Europe relations. As a diagnostic tool, the framework offers considerable clarity. It explains why a nation situated in the western Pacific has committed itself so unequivocally to a European theater of war. Yet the framework, by design, privileges the unit level of analysis. It places Japan at the center, without fully accounting for the systemic pressures imposed by great-power rivalry, alliance decay, and the erosion of deterrence. The risk is analytical overreach: overstating what Japan alone can do to shape outcomes in Ukraine.

Still, that critique must be weighed against reality. Few states today possess the combination of strategic foresight, institutional credibility, and diplomatic agility necessary to bridge the Indo-Pacific and Euro-Atlantic theaters. Japan is one of them. That its leaders have chosen not to sit idly by—despite geography, pacifist traditions, and constitutional constraints—speaks volumes.

A second analytical gap stems from the relative underemphasis on the United States, the fulcrum of the postwar order and now its most volatile variable. With the inauguration of the second Trump administration in January 2025, American policy shifted from strategic commitment to conditional disengagement. Washington has pivoted from arming Ukraine to brokering a peace deal likely to favor Moscow. This reversal has jolted the foundations of the transatlantic alliance. Yet even as the United States steps back, Japan has stepped forward.⁴⁶

When US intelligence support to Ukraine was suspended, Tokyo quietly filled part of the void, leveraging its commercial satellite firm iQPS to provide geospatial intelligence. In concert with Finland’s ICEYE, and the radar capabilities of Germany and Italy, Japan helped restore what the US National Reconnaissance Office once supplied.⁴⁷ This act was not merely technical; it was political. It signaled to both allies and adversaries that Japan intends to remain operationally relevant—even without Washington’s hand on the tiller.

Amid these disruptions, four truths endure. First, Russia’s war aims remain unchanged: the subjugation of Ukraine and the reassertion of imperial control.⁴⁸ Should Moscow succeed, Beijing will conclude that it, too, can achieve its objectives—Taiwan, the South China Sea—at an acceptable cost. Second, this war is not a morality play between democracy and authoritarianism.⁴⁹ It is the blunt contest between an aggressor and a sovereign state defending its survival. The stakes are legal, territorial, and existential. Third, states must take responsibility for their own defense. In an age where alliance commitments come with strings, self-reliance is no longer aspirational—it is imperative. Fourth, and most decisively, Japan–Europe security relations are not just deepening; they are hardening into something strategically durable.

In April 2025, NATO Secretary General Mark Rutte’s visit to Tokyo marked a new phase. Japan joined NATO’s Security Assistance and Training mission for Ukraine—beyond the aid already flowing. His tours of the Yokosuka Naval Base and Mitsubishi Electric’s Kamakura Works were more than optics; they were the visible contours of a growing NATO–Japan defense-industrial nexus.⁵⁰

Though this article has centered on Japan’s engagement with NATO and the G7, the broader trajectory is unmistakable. Japan has forged a Security and Defense Partnership with the European Union and is building strategic ties with a constellation of European states—Italy, Lithuania, Norway, Poland, and Sweden among them. Russia’s invasion of Ukraine did not merely alter European security; it catalyzed a transregional realignment. And as America’s reliability wavers, Tokyo has emerged not as a substitute for Washington, but as a strategic amplifier—binding Europe and Asia through shared threat perception, operational cooperation, and a common resolve to prevent the return of conquest as a tool of statecraft.

Japan is no longer merely reacting to the tectonics of great-power competition. It is positioning itself as a geopolitical fulcrum—one that understands that the defense of Kyiv and the fate of Taiwan are not distant problems, but twin fronts in the same global struggle. ♦

Dr. Nanae Baldauff

Dr. Baldauff is a senior associate fellow at the NATO Defense College and an associate research fellow at the United Nations University Institute on Comparative Regional Integration Studies (UNU-CRIS) in Belgium, as well as a senior researcher at Keio Research Institute at SFC, Japan. She is the author of Japan’s Defense Engagement in the Indo-Pacific: Deterrence, Strategic Partnership, and Stable Order Building (Springer, 2024) and has published extensively on space security and the defense industry. A recipient of the Japan Foundation fellowship (2021), she earned her PhD in political science from Ghent University in 2022. She was the first Japanese national to serve as a research fellow at the NATO Defense College (2024), where she also mentored academic programs. In addition to lecturing at various universities, she sits on the board of the International Security Industry Council Japan.

Notes