Shifting Alliances and Militarisation in South and Southeast Asia

The South and Southeast Asia region is often defined by its diversity, high economic growth rate and strategic significance. However, it is also shaped by territorial disputes which lead to increased militarisation and the aspiration for major powers to flex their muscles. Furthermore, the shrinking civic space in the region brought about by censorship and militarisation, continues to undermine anti-corruption efforts, democratic participation and reform, government accountability and the protection of human rights.

The United States (US) has for years been a major player in the shaping of foreign policy but its influence is being threatened in the current geopolitical landscape where power and influence is much more diffused. The gradual shift in both international and regional relations has seen the rise of China and India in a complex security landscape propelled by disputes and which neither of them has shied away from.

While economic and security integration is likely to fuel power struggles and heighten tensions in the region thereby reshaping the conventional security paradigms, military alliances accentuate the need for holistic approaches in attaining regional stability. This article therefore examines emerging security dynamics and regional integration in the wake of China’s regional posturing and evolving alliances in South and Southeast Asia.

Southeast Asia

Although a significant locus in the growing strategic antagonism between Beijing and Washington, Southeast Asia has become more unstable with an upsurge in naval confrontations: a 15% increase in the first quarter of 2025 as opposed to the previous period.¹

Nonetheless, all SEA states have moderately strong bonds with Beijing including access to the Chinese market. Beijing strives to gain a foothold and challenge US influence in SEA as evidenced through its infrastructure investments and its expansion in security alliances. Beijing’s ambitious Belt and Road Initiative (BRI) has intertwined the region

into a colossal web of infrastructural investments and trade pacts, promoting development while at the same time creating dependencies. As per current estimates, BRI-affiliated investments have resulted in a 5% infrastructural annual increase across the region.² However, augmented indebtedness and dependence on Chinese funds affect the bargaining capability of host countries making them more susceptible to political and strategic influence which in turn has substantial impact on national security due to reduced strategic independence.³

While the US seeks to reinforce alliances in SEA, China continues to be a strategic player and has strived to amplify its mounting politico-economic influence by tapping into its soft power as is the case with cultural, educational and professional collaborations.⁴ For example, Beijing plays a significant role in the construction of hydroelectric plants and solar farms in Cambodia and Laos, amplifying their energy safety while incorporating them into a China-driven economic framework. The BRI has also directed investment into key infrastructure projects such as Indonesia’s high-speed railway linking Jakarta to Bandung, the Laos-China Railway (LCR), and Malaysia’s East Coast Rail Link.⁵

However, some countries in the region see China as a threat as reported in the 2025 Asia Pacific Security Summit where more than 60% of Association of Southeast Asian Nations (ASEAN) member states viewed China as the main threat to economic independence and territorial integrity.⁶ For instance, the South China Sea disputes, an epicentre of hostility with territorial feud involving China, Brunei, Malaysia, the Philippines and Vietnam, threaten trade routes and undermine regional stability as well as the US-China contention which has profound impact on alliances, security and trade.⁷ China’s mounting tensions present a significant challenge in SEA resulting in countries adopting a leery proactive approach while dealing with Beijing. This is a window of opportunity for the dominant regional contender, the US, to solidify its regional engagement.⁸

With China’s maritime aggressiveness, SEA nations pursue security alliances to protect themselves from Beijing’s aggression. For instance, Washington has bolstered its defence collaboration with the Philippines, dilating the Enhanced Defense Cooperation Agreement (EDCA) which allows American troops to use central bases close to the contested waters.⁹

The region also experiences other considerable challenges, for example: climate change and its geopolitical balance in which ecological degradation, extreme weather, and rising sea levels revamp strategic interest with Vietnam, Thailand and Indonesia facing significant risk thereby prompting partnerships on disaster resilience; economic integration challenges like digitalisation, economic dependency and trade imbalances which impact long-term stability; and political instability as is the case with Malaysia, Myanmar and Thailand which have significant impact on human rights and the region’s stability especially when civil strife spills over.¹⁰

South Asia

While India continues to be a dominant power in South Asia due to its growing economy, military, scientific, and technological advancement, the growth of China’s influence transforms the balance of power and mirrors wider shifts in economic multipolarity, challenging conventional trade dynamics dictated by western powers. For example, Beijing’s engagement through its bilateral alliances centred on trade deals have reinforced its place in the region and contested traditional power dynamics hence its major transformation in its foreign policy.

Washington on the other hand has overlooked other countries in the region owing to its affiliation with New Delhi. Delhi’s dominance is thus significant in regional and economic security as it upholds bilateral relations with neighbouring states while encountering decades-old geopolitical challenges with Beijing and Islamabad.¹¹ For instance, Delhi has controlled Thimphu’s foreign policy since the 1949 Treaty of Friendship and still retains significant influence. Additionally, it has amassed significant power in Kathmandu through its investments and influence on its economy.¹²

However, more recently there has been a gradual shift against New Delhi in the region. Nations that had enjoyed strong ties with Delhi have swiftly transitioned recently to warming up to Beijing. For example, Muhammad Yunus, Bangladesh’s Interim Leader, has sidelined Delhi and instead embraced Beijing which has so far provided billions in assistance and infrastructural projects.¹³ Islamabad’s significance in the region also challenges India’s position as displayed through its alliance with Beijing, its border with India and its strategic position linking South Asia to Central Asia.^{14 15} The current India-Pakistan conflict has equally seen Islamabad utilise advanced Chinese air-to-air missiles, defence systems and modern fighter planes.¹⁶

Bangladesh has similarly evolved into a central role in regional integration, bolstering trade and transport routes with India and SEA whereas Sri Lanka is positioned at a vital maritime intersection and maintains relations with China, India and the US.¹⁷ Afghanistan, Bhutan and Nepal equally play crucial roles in the region’s stability often dictated by Beijing and Delhi’s conflicting interests.¹⁸ Furthermore, regional security concerns like insurgency and terrorism complicate military action in the region. South Asia for instance has been an epicentre for non-state armed groups and terrorist organisations thereby impacting regional stability. In addition, the Afghanistan-Pakistan-India-China border tensions stir up disputes in the region.¹⁹

Militarisation

With militarisation being a global benchmark rooted in comprehensive strategic alliances, balancing the presence of a major power is accompanied with its own challenges. For instance, Beijing’s assertiveness in South and Southeast Asia has transformed the military operational landscape in the region prompting increased collaboration amongst states thereby shaping the spheres of influence in the region. For instance, alliances like the Cobra Gold exercises, SEA’s longest-standing military exercises which comprise command and control drills, counter-drone strategies, cyber defence, field operations, humanitarian assistance and space operations, portray Washington’s position in fostering strategic collaboration.²⁰

As part of its attempt to fortify its military and economic dominance, China is meticulously reinforcing its defence industry. Moreover, compared to the US, China has become exceptionally fast in obtaining weapons systems.²¹ Beijing therefore aspires to expand its military capability and establish primary control in the region. On top of securing naval power, Beijing has set out a continuous campaign of creating and militarising artificial islands in the South China Sea.²² Nevertheless, it has made the reunification of Taiwan a primary focus and has disputed the Philippines’ claim over islands in the South China Sea. China’s increasing military power therefore poses a potential risk to countries which are forced to boost their defence by collaborating with Beijing’s rival, the US, for security.²³ While military capabilities continue to evolve, the role of the military is also expanding to responding to growing challenges like natural disasters and regional disputes.

Shifts in Alliances

The rise of China has not only been accompanied by security issues, but also economic wrangles as is the case with the recent tariff war between Washington and Beijing in which President Trump sought to reset the foundations of international trade and saw Beijing reciprocate the tariffs to what was viewed to be a trade embargo and a clear indication of Beijing’s influence.²⁴

Based on a mid-2025 survey conducted amongst ASEAN defence officials, approximately 72% were in support of a more inclusive security approach that minimised the dependency on any single power.²⁵ Countries like Indonesia and Malaysia have thus increased counter terrorism actions to tackle issues which require partnership with neighbouring states. The two countries in collaboration with the Philippines also actively participate in operations against militia groups and piracy in the region. The regional security landscape has also seen Vietnam, Thailand, Malaysia and Indonesia develop robust military systems to deal with threats in addition to taking part in multilateral activities which expand military interaction and their efficiency in responding to threats. Malaysia, the Philippines and Vietnam have similarly strengthened their relations with other partners like the European Union, Japan and India.²⁶

Furthermore, following humanitarian fund cuts and a reduction in global development in a region which is regarded as a relatively closed environment for civil society, increased reliance on China for development and the military for humanitarian aid, further isolates the civil society from decision-making and national dialogue. This risks exacerbating corruption, inequalities and repression which further poses a threat to long-term stability in the region.

Conclusion

An arms race in the quest for geopolitical interests in South and Southeast Asia is at the expense of the populations due to growing inequalities, derailed development and curtailed humanitarian support. The civic space has also not been spared as it continues to shrink in the wake of censorship and authoritarian regimes.

Besides utilising its expanding military prowess to assert its regional foreign policy, China is leveraging alliances with other anti-American nations like Russia to challenge the US’ global dominance and coin a new global order with a more prominent role for China. By embedding itself as a key actor in the international sphere, Beijing has given rise to alternative power.

The shift in alliances is therefore a window of opportunity for powers like China and India which are building considerable long-standing strategic partnerships to assert their influence in the region. While military alliances boost might and present a united front against any aggression, militarisation has also fuelled repression and escalated tensions with different factions thereby spiralling conflicts in the region. With militarisation dancing on the edge of fire, the major powers should engage with each other in mutual interest like defence, climate change and regional economic integration thereby avoiding unnecessary hostility which could spiral into a full-scale war.