Written by Emilie Sterna

07 July 2025 

China’s growing military and economic influence in the Indo-Pacific region has shaped  regional security dynamics. As early as the 2000s, Japan became concerned about the rise of the  People’s Republic of China (PRC). As a result Japan help to establish the QUAD, a diplomatic  partnership with Australia, India, and the United States, to promote stability in the Indo-Pacific. In  parallel, Japan has continued to strengthen its own defence capabilities. By moving toward  remilitarisation, Japan is challenging its long-standing tradition of pacifism and the constraints of its  own constitution. This article aims to analyse the evolution of Japanese defense policy, focusing on  remilitarisation and constitutional revision, as well as the prospects for the creation of an Asian  security organisation in response to China’s ascendancy.

The Acceleration of Japan’s Remilitarisation 

Japan is marking a huge shift from its post-World War II position as a pacifist nation by  dramatically accelerating its remilitarisation. Recently, Fumio Kishida, Japanese Prime Minister  from 2021 to 2024, boosted Japan’s militarisation by approving three new policy documents: the  National Security Strategy (NSS), the National Defence Strategy, and the Defence Buildup  Programme. These policies aim to increase the defence budget in order to strengthen Japan’s  military capabilities. Therefore, the Kishida government plans to grow annual defence spending to  2% of GDP by 2027. This initiative shows a change in Japan’s previous security policy. Indeed,  from 1960 to 2020, the Japanese defence budget was always below or equal to 1% of GDP.  Furthermore, Japan has also decided to acquire and deploy new counterstrike capabilities, enabling  it to target enemy forces beyond its own territory.

This change in Japan’s path to remilitarisation is due to the rise of numerous regional  threats, including China, North Korea, and Russia. Firstly, China has rapidly expanded its military  power and influence in the region, notably by increasing its nuclear arsenal, missile, and naval  capabilities. Moreover, China often intrudes near the contested Senkaku/Diaoyu islands, as well as  claiming maritime and land territory in the Indo-Pacific region, especially its claim over the island  of Taiwan, which escalates tensions between the Beijing and Taipei governments. These claims are a threat to Japan’s security due to its reliance on imports and trade routes that could be disrupted by conflict. That is why the NSS has described China as “the greatest strategic challenge” to Japan and  regional stability. Furthermore, North Korea’s advancements in terms of ongoing missile and  nuclear developments, including the ability to target Japan and US bases, have pushed Tokyo to  invest in advanced missile defence systems. Finally, Russia’s invasion of Ukraine shocked Japan  and reinforced concerns about unresolved territorial disputes such as the South Kuril Islands. Russia  has also increased its military activities around the Kuril Islands. In addition, China and Russia have  conducted joint military exercises near Japan. For all these reasons, Japan is building up its military  capabilities to better protect its economic interests, given its dependence on energy imports and  global supply chains, in response to rising regional threats. However, the remilitarisation of Japan  has been criticised by China, North Korea, and Russia, who accuse Japan of increasing security  risks in the region.

The acceleration of Japan’s remilitarisation is also explained by the expectations of  international partners, including the United States. Indeed, the US expects Japan to assume a  security role that matches its economic and technological power. As a result, instead of keeping its  military activities very limited as in the past, Japan is being encouraged to take on greater  responsibility in collective defence. Thus, Japan has expanded security partnerships to reinforce  regional stability. It has closer ties with Australia, India, the United Kingdom, and Italy by  participating in joint military exercises, dialogues, intelligence sharing, and having mutual access to  each other’s military facilities. For instance, in December 2022, Japan joined the UK and Italy to  develop a new advanced fighter aircraft. In January 2023, Japan signed a defence agreement with  the UK, which has been criticised by China. Japan made a similar pact with Australia in 2022. In  addition, Japan and the US have been working together for deeper military integration, as the US Japan alliance remains the foundation of Japan’s security policy. These partnerships aim to  strengthen collective deterrence and resilience across the Indo-Pacific.

Constitutional Revision and the Evolution of Japan’s Defence Doctrine 

Japan’s defence doctrine has undergone a profound transformation in recent years, driven by  evolving security threats and the reinterpretation of its pacifist constitution, particularly Article 9,  which was imposed after World War II to prevent Japan from maintaining war potential and  engaging in any acts of belligerency. Article 9 of the 1946 Constitution renounces war and prohibits

the maintenance of traditional military forces or the use of force to settle international disputes. For  2

decades, the Japanese government strictly followed this clause, allowing only the maintenance of  the Self-Defense Forces (SDF) as a minimal means of protecting the nation in the event of direct  attack. Offensive capabilities and participation in collective defence were explicitly avoided.  However, in 2015, former Prime Minister Shinzo Abe allowed the SDF to engage in overseas  combat missions, as well as to provide material support to allies in combat zones. This marked a  significant departure from Japan’s previous exclusively defence-oriented posture, prompted by the  rise of numerous regional threats. As a result, the government now interprets Article 9 as permitting  the minimum necessary force for self-defence, including participation in collective security  arrangements under certain circumstances.

Despite these changes, constitutional revision remains a controversial issue in Japan, with  ongoing debates about the legitimacy of reinterpretation versus formal amendment. Indeed, Japan’s  legal framework uses shifting interpretations rather than direct constitutional reform regarding  military forces. These changes create a gap between law and reality, dividing public opinion, which  is fearful of a shift toward a more offensive military posture. This represents a significant move  away from postwar pacifism, with broad implications for domestic politics and regional security. As  Japan continues to strengthen its military capabilities and deepen its security partnerships, the  evolution of its defence doctrine demonstrates a delicate balance between preserving its pacifist  legacy and responding to the urgent demands of a rapidly changing strategic environment. Japan  redefining its defence doctrine and expanding its security role raises the question of whether the  region is moving toward a more formalised collective security arrangement, such as an “Asian  NATO”, and what such a organisation would mean for regional stability and cooperation.

Toward an “Asian NATO”: Prospects and Challenges for Regional Security 

The idea of establishing an “Asian NATO” (a collective security alliance in the Indo-Pacific  region modelled on the North Atlantic Treaty Organization (NATO)), has attracted increasing  attention as regional tensions rise, particularly due to China’s assertive military posture and North  Korea’s nuclear ambitions. Japanese Prime Minister Ishiba Shigeru has long advocated the creation  of such an alliance, arguing that it would provide a united front to deter aggression, much like  NATO’s Article 5 (which holds that an attack on one member is considered an attack on all).  Although this proposal contradicts Article 9 of Japan’s constitution, the evolution of Japanese

security thinking can be explained by Japan’s reduced reliance on the United States for security and  3

its shift towards a more active regional leadership role. Ishiba’s vision for an Asian NATO would  include Japan, South Korea, Australia, India, and ASEAN states willing to participate. While  Taiwan would unsurprisingly be excluded, its strategic importance makes it an essential informal  component of any regional security framework. Proposals for an Asian NATO often involve  integrating existing alliances such as ANZUS, the QUAD, the US-Japan Alliance, and the US-South  Korea Alliance to deter China and strengthen regional security. However, this ambitious plan faces  numerous obstacles.

First of all, US scepticism is evident, as both the Trump and Biden administrations have  shown little enthusiasm for the idea. Notably, Trump has already criticised NATO and prefers  bilateral agreements. Secondly, major regional powers, including India, have expressed scepticism  about joining a formal military alliance, citing strategic non-alignment and ongoing territorial  disputes with neighbours such as Pakistan. Japan’s constitutional Article 9 presents as well legal and  political barriers, which limit its ability to engage in collective defence, further complicating the  prospect of replicating NATO’s model in Asia. In addition, historical animosities and unresolved  issues among potential member states persist, despite recent efforts to strengthen bilateral security  ties in response to shared threats from North Korea and China. Moreover, the lack of unity on how  to approach China, as well as differing threat perceptions and security priorities among Indo-Pacific  nations, make consensus on a NATO-like alliance highly unlikely. While the concept of an Asian  NATO continues to generate discussion as a long-term strategic goal, most analysts agree that the  region is not yet ready for such a formal alliance. Instead, the focus is likely to remain on deepening  existing partnerships and building trust among regional actors.

In conclusion, as Japan continues to strengthen its defence capabilities and adapt its security  doctrine in response to shifting regional dynamics, its path toward remilitarisation and  constitutional revision reflects both necessity and deep-seated caution. The prospect of an „Asian  NATO” remains distant, but Japan’s growing assertiveness and expanded partnerships signal a new  era of proactive security engagement in the Indo-Pacific. Ultimately, Japan’s evolving stance is  reshaping not only its own defence landscape but also the broader balance of power in Asia.

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Australian Government Department of Foreign Affairs and Trade. (n.d.). The Quad. https://www.dfat.gov.au/international-relations/regional-architecture/quad

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Farley, R. (2018, September 20). The Key to Securing the Indo-Pacific: Japanese Constitutional  Reform? The Diplomat. https://thediplomat.com/2018/09/the-key-to-securing-the-indo-pacific japanese-constitutional-reform/

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