Should Southeast Asia Pay Attention to ‘Spheres of Influence’?

The US’ military operation in Venezuela, culminating in the capture and removal of President Nicolás Maduro, may seem geographically distant from Southeast Asia. What matters to Southeast Asia is the logic underpinning the US’ action: a growing willingness to act unilaterally, in this case undermining sovereignty and justifying the use of force through presidential powers against a perceived threat.

More troubling, it raises concerns about the geopolitical concept of spheres of influence, harking back to a time when major powers “staked out” geographical zones, constraining weaker states. Indeed, the US’ 2025 National Security Strategy (NSS) explicitly commits Washington to “reassert and enforce the Monroe Doctrine” (from 1823, identified with the US’ military dominance) through what it terms a “Trump Corollary”, framing the Western Hemisphere as a privileged security space.

Spheres of influence are established when major powers carve up areas according to their interests, sometimes respecting each other’s spheres so as to reduce the chance of disputes or conflict. In the Venezuela episode, no other power challenged Washington’s assertion of a sphere of influence in the Western Hemisphere, because US military power in that area is unparalleled. China has publicly opposed it but is not likely to actively challenge Trump in this instance.

A major power declaring a sphere of influence with little or no active opposition by other powers is rare in world history. When a power declares such a sphere, contesting powers will have to decide whether they want to cede it. Many spheres of influence were established via agreement between two powers. In 1869, Russia assured London that Afghanistan lay outside Russian influence; in 1907, the Anglo-Russian Convention formalised Russia’s agreement to stay out of Afghanistan, enabling the division of Persia into Russian and British spheres.

The US’ action in Venezuela has resurrected some fears about spheres of influence closer to Southeast Asia. However, it is unlikely that the US could unilaterally establish spheres anywhere in Asia without China challenging the move. In any case, the US was more equivocal on Asia in its 2025 NSS, only saying that it would seek to “successfully compete” against China in the Indo-Pacific. 

China declaring a sphere of influence in Asia is also unlikely, simply because the US, with its network of alliances in the region, is unlikely to cede. Even if China seeks to assert such a sphere, regional states, while deeply economically engaged with China, have consistently resisted exclusive alignment with Beijing. Southeast Asian countries have sought to preserve their strategic autonomy through diversification, making true dominance or control by a great power over our hemisphere implausible.

A danger for Asia is indeed a possible divvying up of the region by China and the US, if there is a US-China compact agreeing to carve out respective US- and Chinese-dominated spheres. Such a ‘G-2’ concept is not new. In 2007, a Chinese general had suggested to a US Navy admiral that the two major powers divide responsibilities in the Pacific, with the US operating east of Hawaii and China to the west. In 2023, Chinese President Xi Jinping suggested to then US Secretary of State Antony Blinken that the planet was big enough to “accommodate the respective development and common prosperity” of both countries. More recently, Fudan University don Wu Xinbo wrote that a Sino-US compact could involve a “grand bargain”, suggesting a concept where China continues to support the US dollar and buy US bonds in return for the US stopping its containment of Beijing and reaffirming the ‘One China’ policy.

It is unlikely that a G-2 would happen although Trump’s instincts could facilitate the concept’s acceptance…

The impact of such a G-2 on Southeast Asia would be serious. As William Hurst and Peter Trubowitz note, for the US to seal such a deal, it would have to make concessions on Taiwan and the South China Sea (SCS). This would unravel a security architecture that has underpinned regional stability for decades.

A grand bargain on Taiwan could enable Chinese power projection southward into the SCS, which is disputed by China, Taiwan and several ASEAN states. A concurrent bargain on the SCS could see the US and its partners reducing military exercises and freedom of navigation operation patrols in the area, which would impact claimants such as Malaysia, Vietnam and the Philippines.

It is unlikely that a G-2 would happen, although Trump’s instincts could facilitate the concept’s acceptance: he is allergic to multilateralism and is transactional, especially in deals that would advantage the US. There has arguably been a “tactical pause” between China and the US, with Trump reportedly set to visit Beijing in April. In the ongoing Sino-Japanese crisis over the Japanese premier’s comments on Taiwan, Trump has not openly supported Tokyo, perhaps concerned that this would jeopardise his October 2025 deal with China. Still, this does not mean that a G-2 is likely. While Trump has expressed a desire for a G-2, this remains conceptually woolly; China is cool on the idea, particularly if Beijing is the junior partner.

For now, Trump appears to be more focused on securing an economic deal with China. Moreover, the 2025 NSS asserts Washington’s desire to build a “military capable of denying aggression” in the First Island Chain, together with US allies. This would involve US allies spending more on defence and investing in capabilities to deter (Chinese) aggression; if this happens, it will negate the idea of a G-2. The NSS also notes that a “hostile power” (presumably China) could control the SCS by imposing a “toll system” and “close or open” the vital maritime area “at will”, which would be harmful to US interests.

A US-China G-2 would have deleterious impacts on Southeast Asia. Given the uncertain state of play and lack of coordination between Washington and Beijing, however, regional countries can, for the moment, breathe a collective sigh of relief.

2026/17