“From Exclusive Self-Defense to Active Deterrence” Japan Accelerates Militarization, Reflecting U.S. Strategic Demands and Germany’s Rearmament Trend

End-of-the “Pacifist Japan” Scenario
Expanded Justification for Defense Buildup Amid U.S. Alliance Restructuring
Germany’s Rearmament Trend Also Catalyzing Japan’s Policy Shift

Japan, which has constrained its military autonomy for 80 years since World War II, is now approaching a pivotal turning point. Following the revision of its three core security documents, Tokyo is simultaneously pursuing the operational deployment of counterstrike capabilities and a restructuring of its defense industry, signaling a rapid shift in its security policy from a defense-oriented posture to an active deterrence strategy. Against the backdrop of mounting pressure from the United States to recalibrate alliance structures and the parallel rearmament of Germany, the historical constraints tied to its status as a former aggressor nation are increasingly receding from the center of policymaking.

Takaichi Pushes Security Document Revisions Following Arms Export Policy Shift

According to Kyodo News on the 28th, the inaugural meeting of the “Expert Panel on Security from a Comprehensive National Power Perspective,” established by the Japanese government to revise its three key security documents, was held the previous evening at the Prime Minister’s Office. The panel comprises 15 members, including former Ambassador to the United States Kenichiro Sasae, former Vice Defense Minister Tetsuro Kuroe, University of Tokyo Graduate School of Public Policy professor Kazuto Suzuki, and Waseda University professor Noriko Endo.

The formation of this panel follows Prime Minister Sanae Takaichi’s pledge during a parliamentary address in October last year to revise the three cornerstone security documents—namely the National Security Strategy, the National Defense Strategy, and the Defense Buildup Program—within the year. At the meeting, Takaichi stated, “The relatively stable international order that persisted after the Cold War has become a relic of the past,” adding, “We must proactively pursue a fundamental strengthening of our defense capabilities.” She also emphasized the need to examine new modes of warfare and establish systems capable of sustaining prolonged conflicts, referencing Russia’s invasion of Ukraine and evolving conditions in the Middle East.

Japan’s security policy is guided by three principal documents. The first is the National Security Strategy (NSS), which serves as the highest-level directive for foreign and security policy, defining how Japan perceives and responds to threats. The second is the National Defense Strategy (NDS), a military strategy document derived from the NSS that outlines the role of the Self-Defense Forces, operational concepts, and force deployment direction. The third is the Defense Buildup Program (DBP), an execution roadmap detailing specific weapons acquisitions, budgets, and force enhancement plans. These three documents are interlinked, forming a “blueprint–strategy–budget” framework for Japan’s security policy. The most recent revision occurred in 2022, when Japan formally declared its possession of “counterstrike capabilities,” signaling a major policy shift.

The upcoming revisions are expected to reflect changes in the international security environment since 2022. Beyond the military expansion of China and North Korea, the prolonged Russia-Ukraine war and the conflict between the United States and Israel and Iran that began in February this year have significantly altered both the security landscape and the nature of warfare. Accordingly, measures such as deploying long-range missiles, refining strike systems, and strengthening command and control frameworks are likely to be included, with the aim of elevating previously declaratory “counterstrike capabilities” to operational readiness.

A central issue will be preparedness for “new modes of warfare.” In conflicts involving Ukraine and Iran, large-scale deployment of low-cost drones and the rapid proliferation of artificial intelligence (AI) applications have become defining features. Given the limitations of existing equipment systems in addressing these developments, how Japan adapts to such changes will emerge as a key point of contention. Another focal issue is the establishment of “sustained combat capability,” enabling prolonged military engagement. Experts underscore that strengthening the domestic defense industrial base is essential to ensure the autonomous procurement of ammunition and weapons in times of crisis.

Ahead of the expert panel meeting, the Japanese government had already abolished the “Three Principles on Transfer of Defense Equipment,” which had restricted the export of lethal weapons, on the 21st. By removing provisions that limited exports to five categories—rescue, transport, warning, surveillance, and minesweeping—the move effectively opens the door to the export of lethal arms. This is intended to bolster the competitiveness of Japan’s defense industry while enhancing its combat readiness in contingency scenarios. At the meeting, Takaichi reiterated her firm commitment to strengthening defense capabilities, declaring that “there is not a moment to spare.”

U.S. Demands Expanded Japanese Role as a Pillar of Indo-Pacific Strategy

At its core, the revision reflects a transformation in the character of Japan’s security policy. As a former aggressor nation in World War II, Japan has long adhered to the principle of “exclusive self-defense,” exercising only the minimum necessary force in response to an attack under its postwar pacifist constitution. Recent developments, however, point in a different direction. The acquisition of preemptive strike capabilities, the possession of long-range offensive assets, and the expansion of multilateral security cooperation beyond the U.S.-Japan alliance all indicate a transition from passive defense to active deterrence.

This transformation is unfolding with tacit approval or strategic utilization by the United States. Japan’s postwar security strategy has historically operated on a framework of “trading autonomy for security.” Under the San Francisco Treaty system, Japan restrained military expansion under Article 9 of its constitution while accepting U.S. military protection through the U.S.-Japan Security Treaty. Within this arrangement, Japan adopted the “Yoshida Doctrine,” prioritizing economic development while relying on the United States for security, thereby sustaining an asymmetric alliance structure centered on U.S. leadership.

This framework persisted after the Cold War. During major international conflicts such as the Gulf War (1990–1991) and the War on Terror (2001–2021), Japan refrained from direct military intervention while expanding financial and logistical support, adjusting its mode of alliance contribution. At the same time, as the security environment in Northeast Asia deteriorated, Japan’s dependence on the United States intensified. Consequently, Japan has faced the dual challenge of expanding military autonomy while maintaining alliance dependence, a dynamic often characterized in academia as a “tension between relinquished autonomy and secured deterrence.”

However, the second Trump administration has introduced a shift in U.S. strategic expectations toward Japan. According to the National Security Strategy released in December last year, Washington is simultaneously demanding a structural recalibration of the alliance and a redefinition of Japan’s national security identity. The sustainability of the alliance, it argues, must be underpinned by tangible actions such as strengthening Japan’s defense capabilities and enhancing its autonomous operational capacity.

Japanese political circles interpret the Trump administration’s NSS as explicitly reaffirming the “conditional nature of alliances.” Rather than emphasizing values-based alliances, the United States is redefining partnerships in transactional terms, prioritizing tangible contributions to its security and economic interests. This shift indicates that the U.S. no longer provides military protection as a public good, instead moving toward a transactional alliance model predicated on mutual contributions. At present, Washington’s foremost priority is countering China. To this end, it requires a regional actor capable of sharing the burden in East Asia, with Japan emerging as the optimal candidate. From the U.S. perspective, Japan’s rearmament effectively serves as a cost-saving mechanism.

Germany’s Military Return Provides Additional Justification for Japan’s Rearmament

Germany’s rearmament is also providing strategic justification for Japan. Following Russia’s invasion of Ukraine, Germany declared a “Zeitenwende” (historic turning point), elevating its defense spending this year to over 100 billion euros and positioning itself among the world’s top military spenders. It is advancing military expansion outside traditional fiscal constraints while increasing troop levels and debating the reinstatement of conscription. On the 22nd of this month, Germany also unveiled a comprehensive military strategy titled “Overall Concept for Military Defense.” This marks the first time since the establishment of the Bundeswehr in 1955 during the Cold War division of East and West Germany that Berlin has formulated such a comprehensive strategy.

Under the subtitle “Responsibility for Europe,” the document emphasizes Germany’s status as Europe’s largest economy and the largest NATO ally without nuclear weapons, declaring its intent to assume a leading role as the central pillar of continental defense. It also sets the goal of building one of Europe’s most powerful conventional military forces while expanding the scope of military engagement beyond national defense to a global scale. This signals a departure from regionally confined defensive strategies toward the development of capabilities capable of conducting operations worldwide when necessary.

Germany’s policy shift is driven by heightened threat perceptions regarding Russia and the strategic pivot of the United States. Berlin assesses that Russia’s military threat has reached unprecedented levels and is preparing for the possibility of direct military provocations against NATO in the medium to long term. In particular, it identifies the expansion of hybrid warfare—combining cyber and information operations—and the increasing pressure exerted through long-range strike capabilities as key risks.

This sense of urgency is translating into concrete military restructuring. Germany has outlined a phased force modernization roadmap targeting 2039. Phase one (2026–2029) focuses on building a force capable of immediate combat readiness; phase two (2029–2035) aims to position Germany as a leading NATO military power; and phase three (2035–2039) envisions the completion of a “technologically superior military” integrating advanced innovations. The plan includes securing a total force of 460,000 personnel—260,000 active-duty and 200,000 reservists—as well as long-range precision strike weapons. Germany amended its constitution last year to remove limits on defense spending and has set this year’s defense budget at 108 billion euros, an increase of more than 25% from the previous year.

Germany’s rearmament, as a fellow former aggressor nation, is serving as a powerful factor legitimizing Japan’s discourse on becoming a “normal military power.” A military security expert noted, “With Germany moving toward rearmament, the argument that Japan alone should be constrained due to its past as an aggressor nation has lost much of its persuasive force,” adding, “As security threats materialize globally, deterrence capability in the present is increasingly replacing historical responsibility as the central criterion in policymaking.”