Scenarios of a possible annexation of Taiwan

Edited by Federica Masellis

Introduction

In a regional scenario marked by competition between China and the United States, Tokyo has to deal with the potential fallout of the Taiwan crisis: regional instability, migration flows, economic turmoil and possible Chinese military reactions. Considering recent transformations in Japanese defence policy, the situation calls for reflection on how to strengthen national security, redefine international alliances and, at the same time, consider a more active role as a regional mediator. This paper examines the dimensions the impact of historical ties with Taiwan on Japan’s future posture in East Asia.

The Geopolitical Context

Japan’s current geopolitical context is influenced by its geographical location, which places it at a crucial strategic point within the Asian security dynamics. China, with its growing military power projection and territorial ambitions in the South China Sea, poses a direct challenge to stability in the region. Moreover, the reorientation of the US military force – which has traditionally ensured Japan’s security – has only intensified the urgency for Tokyo to reconsider its defensive and diplomatic strategies[1].
The Taiwan issue emerges as one of the most significant points of tension in the region. A potential conflict between China and Taiwan could directly affect Japan, given its geographical proximity and economic ties.[2] Japan must therefore assess its policies in relation to Taiwan’s defence, including the evaluation of possible military assistance and the strengthening of cooperation with allies such as the United States and Australia, in the context of joint military exercises and intelligence exchanges.[3] Moreover, Tokyo is involved in increasingly insistent demands for a strategic role in multilateral alliances, such as the Quadrilateral Security Dialogue (QUAD)[4], which emphasises the need for a collective approach to regional security.[5]
In such a landscape, Japan faces the challenge of balancing its historical pacifist norms with the growing need for defence and deterrence. This situation prompts a reassessment of national security policies and the possibility of enhancing military capabilities.

The Annexation of Taiwan and its Implications

The Taiwan issue is historically complex, rooted in a conflict that originated in 1949, when the Chinese nationalist government, the Kuomintang, fled to the island after being defeated by the communists. Since then, Taiwan has developed a distinct national identity, while maintaining a status as a ‘republic’ not recognised by most nations, including restrictions imposed by Beijing, which considers Taiwan as an integral part of its territory. Taiwan’s integration into mainland China cannot be viewed solely through the lens of territorial sovereignty; it also involves the restructuring of economic, cultural and military relations in the region.[6]
The implications of such an annexation would extend far beyond a simple change in legal status. Economically, Taiwan plays a crucial role as a global technology hub. The absorption of the island by China could lead to significant dislocations in this sector and consequent problems for the companies involved. [7] On the other hand, the reactions of the international community would be expected to be strong and immediate. The United States, committed to supporting Taiwan through the Taiwan Relations Act ^[8], could be pushed to respond militarily or through economic sanctions, triggering a potential escalation of regional tensions involving alliances such as that between the US and Japan.[9]
The weakening status quo in East Asia could push Tokyo to review its defence posture and alliance strategies, prioritising an updated collective defence policy, potentially working more closely with US allies to ensure regional balance. In this scenario, Taiwan’s security is not only a Sino-US bilateral issue but also becomes crucial for Japanese security and the stability of the entire Asia-Pacific region.

US Foreign Policy under Donald Trump

US foreign policy under Donald Trump has shown a significant departure from traditional US multilateral strategies, favouring a realpolitik approach based on concrete national interests, summarised in the slogan ‘America First’. This orientation has resulted in a more ambiguous relationship with historical allies and greater scepticism towards international institutions on the US side, favouring instead bilateral relations and direct contacts with authoritarian leaders such as Kim Jong-un and Vladimir Putin. The US strategy of protecting its interests has raised concerns among historical allies, especially in the context of China’s growing assertiveness on the world stage.[10]
In parallel, the reduction of defence spending has been a hallmark of Trump’s foreign policy. Although Trump promoted the modernisation of the armed forces, he also pushed for a review of the costs of NATO alliances and a greater sharing of expenses among members. This created tensions with NATO partners, many of whom were not meeting the 2 per cent of GDP target for military spending but also opened a debate on the need for mutual accountability within strategic alliances. Trump’s approach highlighted the need for Japan and other regional actors to increase their defensive capabilities in a context of growing instability, in anticipation of possible crisis scenarios related to Taiwan and China’s response to possible foreign provocations.[11]
In the analysis of US foreign policy under the Trump presidency, the concept of realpolitik emerges as a strategic fulcrum in outlining the new American approach to Japan and Asian security more generally. Realpolitik focuses on practical and utilitarian rather than ideological considerations, favouring bilateral relations based on tangible national interests rather than the promotion of democratic values or human rights. In this context, the geopolitics of the Asia-Pacific region, particularly the tensions related to China and the possible destabilisation of Taiwan, has forced the United States and its allies, such as Japan, to reconsider their security strategies. The Trump government has taken direct steps to increase its military presence in Japan through joint exercises and the transfer of military technology, a clear sign of its desire to establish an effective deterrence against Chinese expansion.[12]
Overall, Trump’s foreign policy has initiated a phase of rethinking international relations and defensive strategies in the Indo-Pacific, urging Japan to redefine its role in a context of increasing geopolitical instability.

Japan’s Possible Responses to the Annexation of Taiwan

Japan faces a rapidly changing geopolitical environment due to possible developments concerning Taiwan, which could have serious repercussions on national security and regional stability. A possible annexation of the island by China would pose a direct threat, prompting Tokyo to review its military and diplomatic strategies.[13]
Militarily, Japan is strengthening its Self-Defence Forces by increasing its budget, adopting advanced technologies (such as drones and air defence systems), and integrating new offensive capabilities. In line with the 2023 National Security Strategy, Tokyo aims for credible deterrence by enhancing joint exercises and interoperability with allies such as the United States, Australia, and India. A multi-domain approach is adopted, including cyber, space and maritime security, with the aim of protecting naval routes and consolidating Japan’s position in the Indo-Pacific.[14]
At the diplomatic level, Japan intensifies cooperation with regional actors and promotes multilateral diplomacy. Through platforms such as the Quad and ASEAN, Tokyo seeks to build a network of alliances to contain Chinese influence and preserve the international rules-based order, particularly with regard to freedom of navigation.[15] In addition, Japan also relies on instruments of economic diplomacy, such as the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP)[16], to strengthen regional resilience and promote a shared vision based on democracy and stability.[17]
In summary, the Japanese response to the potential crisis over Taiwan is based on a dual track: military reinforcement and diplomatic activism, with the aim of guaranteeing its own security and contributing to the stability of East Asia.

Future Scenarios for Japan

The future scenarios for Japan are basically divided into two possible trajectories: an optimistic path, in which the country manages to turn the Taiwan crisis into an opportunity for strengthening and revitalisation, and a pessimistic path, in which Japan faces progressive isolation and economic and strategic decline.
In the optimistic scenario, the stabilisation of the situation in Taiwan creates the ideal environment for Tokyo to intensify its strategic alliances with the US, Quad countries and Southeast Asian nations. This increased military and diplomatic cooperation is accompanied by a profound process of regional economic integration, including restructuring supply chains to reduce dependence on China, expanding trade ties with ASEAN, and adopting shared standards for the protection of freedom of navigation and international rights. On the domestic front, Japan is accelerating the transition to green technologies and digitisation, promoting investment in renewable energy, sustainable mobility and high-tech innovation. This focus on sustainability not only attracts foreign capital but also strengthens the country’s social and economic resilience, projecting it as a leader in shaping future global policies on climate and digital transformation.[18]
In contrast, in the pessimistic scenario an escalation of tensions with China – culminating in direct aggression or pressure on disputed islands such as the Senkaku – brings the regional security architecture to its knees. In the absence of a unified and coordinated response among allies, Japan risks finding itself isolated, forced to reckon with prolonged economic stagnation stemming from the disruption of supplies of high-tech components from Taiwan.[19] Tokyo’s diplomatic weakness translates into a haemorrhaging of foreign investment and a widespread feeling of mistrust towards institutions, while military escalation imposes painful choices, such as the forced expansion of defence spending and the revision of traditionally pacifist constitutional constraints. In this context, the fear of direct aggression pushes the population towards nationalist positions, but the lack of a clear and shared strategy accentuates internal instability, hindering Japan’s ability to react effectively and permanently weakening its role in Asian politics.[20]
Both scenarios emphasise the importance of an integrated strategy that balances military proactivity, diplomatic engagement and economic innovation: only in this way can Japan move towards a stable and prosperous future or at least mitigate the effects of an increasingly uncertain geopolitical environment.

Conclusion

The possible fall of Taiwan prompts Japan to urgently review its strategic profile, combining a strengthening of defence – with increased military spending, modernisation of surveillance systems and closer cooperation with the US and other allies – with an economic diversification that is indispensable to compensate for the disruption supplies of high-tech components. In this new context, Tokyo seeks alternative partnerships in South Korea, Australia and beyond, investing in resilient infrastructure, cybersecurity and advanced technologies. Only an integrated approach that balances military deterrence and economic flexibility through multilateral alliances and innovation will allow Japan to maintain stability, prosperity and autonomy in an increasingly uncertain Asia-Pacific region.

Note

[1] C. MARTORELLA, «Il riarmo del Giappone e la rivincita pop», Manga Academica, vol. 10, 2017.
[2] P. GERVASO, «La rilevanza strategica di Taiwan nello scacchiere internazionale: la minaccia militare cinese», Università di Padova, 2022. https://hdl.handle.net/20.500.12608/57454
[3] M. RAIMONDO, «L’evoluzione della posizione del Giappone all’interno dell’alleanza con gli Stati Uniti verso i conflitti in Zona Grigia ed il conflitto di Taiwan», Università Ca’Foscari Venezia, 2023. https://hdl.handle.net/20.500.14247/18187
[4] Il Quadrilateral Security Dialogue (QUAD) è un forum strategico informale tra Stati Uniti, Giappone, India e Australia, nato con l’obiettivo di promuovere un Indo-Pacifico libero, aperto, inclusivo e basato su regole.
[5] S. EISENTRAUT & B. GAENS, «The US-Japan, India, Australia Quadrilateral Security Dialogue», Indo-Pacific Alignment or Foam in the Ocean?. Finnish Institute of International Affairs, vol. 239, 2018.
[6] P. L. HSIEH, «The Taiwan question and the One-China policy: Legal challenges with renewed momentum», Die Friedens-Warte, vol. 84, n. 3, 2009.
[7] C.-C. KUO, «Economic Globalization Under a New Cold War: Taiwan’s Ambiguous and Critical Role», Asian Economic Papers, vol. 23, n. 3, 2024.
[8] Il Taiwan Relations Act (TRA) è una legge degli Stati Uniti approvata dal Congresso nel 1979, dopo che Washington ha ufficialmente riconosciuto la Repubblica Popolare Cinese (RPC) come unico governo legittimo della Cina, interrompendo così le relazioni diplomatiche formali con Taiwan (Repubblica di Cina). Il TRA è stato creato per regolare i rapporti non ufficiali tra gli Stati Uniti e Taiwan, garantendo che, pur senza riconoscimento diplomatico formale, gli USA potessero continuare a mantenere legami economici, culturali e di sicurezza con l’isola.
[9] S. W. BRENNAN, «Assessing the Legal Framework for Potential US Conflict with China Over Taiwan», International Law Studies, vol. 99, n. 1, 2022.
[10] A. TAIM, «The Impact of Realism on US Foreign Policy during the Trump Presidency», Presidency, vol. 4, 2024.
[11] J. P. KAUFMAN, «The US perspective on NATO under Trump: lessons of the past and prospects for the future», International Affairs, vol. 93, n. 2, 2017.
[12] H. THOMPSON, «The new EU-China trade deal is driven by a commercial realpolitik–and the world knows it», New Statesman, vol. 150, n. 5604, 2021.
[13] B. EMMOTT, «Deterrence, Diplomacy and the Risk of Conflict Over Taiwan», Taylor & Francis, 2024.
[14] T. LE, «Japan and the revolution in military affairs», Journal of Asian Security and International Affairs, vol. 5, n. 2, 2018.
[15] K. KOGA, «Japan’s Strategic Vision on Indo-Pacific Institutions: Quad, Quad Plus and ASEAN Centrality», in India-Japan-ASEAN Triangularity, Routledge, 2022.
[16] Il Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP) è un trattato commerciale multilaterale tra 11 Paesi dell’area Asia-Pacifico e delle Americhe, firmato l’8 marzo 2018 a Santiago del Cile. Nasce come evoluzione del Trans-Pacific Partnership (TPP), dopo il ritiro degli Stati Uniti nel 2017. I membri attuali includono: Australia, Brunei, Canada, Cile, Giappone, Malesia, Messico, Nuova Zelanda, Perù, Singapore e Vietnam. Il trattato copre circa il 13% del PIL mondiale.
[17] S. N. KATADA, «Gatekeeper’s Dilemma: Japan Facing CPTPP Applications from China and Taiwan», in China, Taiwan, the UK and the CPTPP: Global Partnership or Regional Stand-off?, Springer, 2023.
[18] A. E. MAROCCO, «Japan’s national interests in Taiwan», Naval Postgraduate School, 2013. https://hdl.handle.net/10945/34702.
[19] Y. YING, «Japan’s Policy on the Taiwan Issue», Seoul National University, 2023. https://s-space.snu.ac.kr/bitstream/10371/196646/1/000000177828.pdf
[20] S. SUZUKI, «The rise of the Chinese ‘Other’in Japan’s construction of identity: Is China a focal point of Japanese nationalism?», in Identity Change and Foreign Policy, Routledge, 2015.

Photo: Japan Taiwan