The Diet granted Prime Minister Sanae Takaichi a peaceful yet firm majority, which gave her enough political autonomy to operate freely. She now holds the power to advance vital strategic goals, which she believes will shape Japan’s future development. Her security plan, which includes defence budget growth to 2% of GDP and nuclear principal assessment and Japan’s enhanced regional leadership position, represents a major shift from Japan’s historical security posture since World War II. The new direction emerged because Japan needs to counter Chinese military growth while asserting its position as a security force in East Asian regional affairs. The strategic change will create new difficulties for South Korea and China while it forces the U.S.–Japan alliance to deal with new obstacles, which will break down the current regional structure unless diplomats succeed in maintaining open communication and sharing information effectively.

The Japanese government has made a complete shift away from its traditional security practices, which represent a major change in its defence approach. The Japanese pacifist constitution, together with its voluntary nuclear weapons ban since 1945 have maintained stability in the region because of ongoing historical memories from the past. Takaichi shows his willingness to review the non-nuclear principles, which had been considered off-limits for political discussion, which demonstrates his commitment to challenge established strategic principles from the past forty years. The introduction of this new capability creates doubts about whether Northeast Asia will experience an escalation of military competition between nations. The government must handle three major domestic obstacles, which include dealing with public divisions, following constitutional rules and managing the expenses from continuing defence growth. The Japanese government faces two major challenges because of its ageing population and financial responsibilities, which make it hard to sustain a long-term military expansion. The country needs political agreement for its defence strategy, but this agreement remains elusive.

The rising Chinese power in the region has forced Japan to conduct a complete transformation of its strategic framework. The military actions of Beijing against Taiwan, along with its wide ocean territory claims and its fast-paced defence system development, have created a new power dynamic in the region. The developments in Tokyo require the establishment of an effective deterrent system and an active security position for the country. Japan implements its strategy to stop East Asia from becoming a unipolar system, which China would control through its current diplomatic actions. The Chinese government will probably view Japanese military actions as destabilising forces which will help Beijing expand its military power and support domestic nationalist ideologies. The present circumstances have the ability to damage trust relationships, which would endanger crisis management systems and make accidental conflicts more likely to occur.

The country bases its response on its specific national concerns. The Japanese military normalisation process encounters political obstacles because Seoul maintains its disagreement about the unresolved historical matters from previous times. South Korean officials have expressed their worry about Takaichi’s nuclear policy review because they believe it will harm North Korea cooperation and create difficulties for maintaining regional defence systems. The United States and its two Asian allies share common worries about China and North Korea, yet their mutual distrust creates obstacles for their trilateral cooperation. Japan’s forceful actions will create new conflicts instead of creating stability because diplomats must continue their diplomatic dialogue.

The U.S.–Japan alliance, which serves as the base for regional peace, faces multiple new challenges which have emerged. Washington depends on Japan’s pacifist military policy to create a stable security situation because it extends nuclear protection to Japan through its nuclear umbrella. The Japanese government uses strategic ambiguity as a policy, which creates difficulties for U.S. non-proliferation objectives, while Washington must continue to support South Korean confidence through its backing of Japanese defence modernisation programs. The alliance needs to modify its strategy because Japan now functions as a regional power, but the organisation must handle this change with care to defend the entire region from instability. The United States needs to assess how Japan’s new military strategy aligns with its present Indo-Pacific strategy because great-power competition in the region keeps intensifying.

Countries need to keep their communication lines open while using diplomatic approaches to solve their competing national interests. Japan needs to establish open communication about its military transformation, being defensive in nature, to reduce suspicions from neighbouring countries. Enhanced trilateral dialogue with South Korea and the United States is crucial for maintaining unity on shared security challenges, particularly regarding North Korea and maritime stability. The process of working with China proves difficult, yet we must continue our engagement. The prevention of escalation would become possible through three essential elements, which include confidence-building measures, crisis communication channels and discussions about arms-control standards. Japan needs to create diplomatic initiatives which prove its commitment to regional peace as it builds up its defence capabilities. Tokyo needs to present its developing position as a security stabiliser for the region instead of military expansion.

Prime Minister Takaichi has established an agenda which demonstrates Japan’s commitment to creating its own strategic path during a time when the region faces extreme instability. East Asia currently experiences a new era, which brings shifting power structures, while society requires a unifying element to preserve stability. Japan stands ready to take on this position, but its ability to maintain balance in the region depends on its success in gaining confidence from neighbouring countries and keeping its alliances united and proving that its forceful actions serve to protect instead of destroy the current regional structure. Japan should manage its strategic growth to build stronger deterrence capabilities while it supports the rules-based system and creates stability throughout East Asia. The wrong handling of this situation would lead to increasing public doubts about the military, while the military expansion would threaten the security system Japan has built. Japan needs to demonstrate that its current military stance will create stability throughout the region because uncertainty now dominates the entire area.

The opinions expressed in this article are the author’s own.

Ha, H. T., & Tan, E. (2026). Japan’s growing hardpower profile: Implications for Southeast Asia (ISEAS Perspective 2026/8). ISEAS – Yusof Ishak Institute. 

Mahadzir, D. (2026, January 1). Japan’s security faces ‘unprecedented challenges,’ say defence leaders. USNI News. 

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