Geopolitical Competition in Southeast Asia: ASEAN and Maritime Disputes

1. The Strategic Epicenter: Why Southeast Asia Matters

Southeast Asia is not merely a passive stage for great power politics; its geography, economy, and demography make it a prize in itself. The region sits astride some of the world's most critical sea lanes, linking the Indian and Pacific Oceans. Its economies are booming, and it has become a key destination for companies diversifying their supply chains away from China.

To understand why this region has become, as one expert puts it, "the most important arena for this strategic competition," let's start with a foundational reading.

As the report highlights, for the US, the region is crucial for the free movement of trade and military forces and for its allies. For China, it is a critical source of trade, a key component of its Belt and Road Initiative (BRI), and essential for its energy security, as most of its oil imports transit through the Strait of Malacca and the South China Sea. This mutual and intense interest sets the stage for a complex geopolitical game.

2. The Great Power Courtship: Competing for Influence

The US-China rivalry in Southeast Asia is not a simple binary contest. It's a multi-domain competition where both powers use different tools of statecraft to win influence.

• China primarily leverages economic power through trade, investment, and infrastructure projects under the BRI. Diplomatically, it engages through ASEAN-led forums. Militarily, its presence is most felt through its assertive actions in the South China Sea.
• The United States leans on its long-standing security alliances (with the Philippines and Thailand), its military presence, and its "Indo-Pacific Strategy," which promotes a "free and open" region. Economically, it offers an alternative to Chinese investment and has launched initiatives like the Indo-Pacific Economic Framework (IPEF).

This dynamic places ASEAN nations in a position where they are courted by both sides but also pressured to align with one over the other.

Professor Koh's analysis reveals the central dilemma for ASEAN countries: they seek to benefit from the economic largesse of both powers while avoiding being caught in the gears of their security competition. This forces them into a delicate balancing act.

3. Flashpoint: The South China Sea

Nowhere is the US-China competition more tangible and dangerous than in the South China Sea. This body of water is not just a collection of islands and reefs; it is a vital artery for global trade and is believed to hold significant oil and natural gas reserves.

The core of the dispute involves overlapping territorial claims by several countries, set against China's expansive and ambiguous "nine-dash line," which claims sovereignty over nearly 90% of the sea.

To solidify its claims, China has engaged in a massive land reclamation and militarization campaign, turning submerged reefs into artificial islands equipped with runways, harbors, and missile systems—effectively creating a network of unsinkable aircraft carriers.

The following video provides an excellent visual summary of the geopolitics of this critical waterway.

The key takeaways from this are:

• China's Strategy: Create "facts on the water" through physical occupation and militarization to enforce its claims, ignoring international law (like the 2016 Hague tribunal ruling that invalidated the nine-dash line).
• US Response: Challenge China's excessive maritime claims by regularly sailing warships through contested waters in Freedom of Navigation Operations (FONOPs), asserting the rights of all nations to transit through international waters.

This action-reaction cycle between Chinese assertion and US pushback makes the South China Sea one of the world's most dangerous potential flashpoints.

4. ASEAN's Strategy: Centrality and Autonomy

Caught between these two giants, the nations of Southeast Asia have collectively pursued a strategy centered on the concept of ASEAN Centrality. This is the principle that ASEAN, as a bloc, should be the primary platform for regional diplomacy and security architecture, setting its own agenda rather than having it dictated by outside powers.

This strategy is underpinned by the "ASEAN Way"—a process based on consensus, non-interference in internal affairs, and quiet diplomacy. However, this consensus-based model is often tested by the competing interests of its members and the immense pressure from the US and China.

To understand ASEAN's strategic thinking, let's turn to an academic analysis of its response to the great power rivalry.

The paper shows that ASEAN is not a passive victim. By issuing its own statements on regional order (the Outlook on the Indo-Pacific), expanding its network of partners, and insisting on its role as the diplomatic convener, ASEAN actively works to maintain its strategic autonomy. Its goal is to create a regional order that is inclusive and balanced, rather than one dominated by a single power or divided into two hostile blocs.

Conclusion

Today, we've seen that Southeast Asia is a crucial and complex theater in the US-China strategic competition. The rivalry here is not just about abstract influence but about tangible control over vital sea lanes, economic networks, and the regional security order.

Key Takeaways:

• Central Arena: Southeast Asia's strategic location and economic dynamism make it a focal point of US-China competition, with both powers vying for influence using economic, diplomatic, and military tools.
• South China Sea Flashpoint: The maritime disputes in the South China Sea are the most acute manifestation of this rivalry, pitting China's assertive territorial claims and militarization against US-led efforts to uphold freedom of navigation and international law.
• ASEAN's Balancing Act: ASEAN seeks to manage this competition through the principle of ASEAN Centrality, aiming to maintain its unity and strategic autonomy. It strives to avoid choosing sides, instead positioning itself as an inclusive diplomatic hub for the region.
• A Strained Unity: While ASEAN strives for a unified approach, the intense pressure from Washington and Beijing often strains its consensus-based model, as member states have differing threat perceptions and economic interests.

Preview of the Next Lesson:

Having examined the contest for influence in Southeast Asia, our next lesson will move to another increasingly important area of competition. We will analyze the growing strategic competition in the Pacific Islands, including security pacts and resource politics. This will show how the US-China rivalry is expanding to even the most remote corners of the globe.