The South China Sea is a 3.5 million square kilometer body of water bounded by China, Taiwan, the Philippines, Malaysia, Brunei, Indonesia, and Vietnam. Through its waters passes one-third of global maritime trade. Beneath its seabed lie potentially vast oil and gas reserves. And across its waves, the United States and China are engaged in a strategic competition that may define the century.
Geographic Significance¶
Location¶
The South China Sea connects the Indian and Pacific Oceans, serving as the maritime crossroads of Asia:
- To the southwest: The strait-of-malacca and Indian Ocean
- To the northeast: Taiwan Strait and the Pacific
- To the south: Indonesia and Australia
- To the northwest: China’s coast and industrial heartland
For China, the South China Sea is the gateway to the world. For the United States and its allies, it is a critical link in the chain connecting the Pacific to the Indian Ocean.
Islands and Features¶
The sea contains hundreds of small islands, reefs, and shoals:
- Paracel Islands: Controlled by China, claimed by Vietnam and Taiwan
- Spratly Islands: Claimed in whole or part by China, Taiwan, Vietnam, the Philippines, Malaysia, and Brunei
- Scarborough Shoal: Contested between China and the Philippines
Many features are barely above water at high tide—yet they have become objects of intense competition.
Competing Claims¶
The Nine-Dash Line¶
China claims sovereignty over most of the South China Sea based on historical presence, demarcated by a vague “nine-dash line” that encompasses approximately 90% of the sea. This claim:
- Has no clear legal basis under international law
- Was rejected by a 2016 Permanent Court of Arbitration ruling
- Overlaps with the exclusive economic zones of neighboring states
- Is enforced by an increasingly powerful Chinese coast guard and navy
Beijing has refused to accept the arbitration ruling, calling it “null and void.”
Southeast Asian Claims¶
The littoral states assert claims based on the UN Convention on the Law of the Sea (UNCLOS):
- Vietnam: Claims the Paracels and Spratlys based on historical sovereignty and UNCLOS
- Philippines: Claims features within its exclusive economic zone
- Malaysia: Claims features on its continental shelf
- Brunei: Claims an exclusive economic zone overlapping Chinese claims
- Indonesia: Does not claim islands but asserts EEZ rights that China contests
Taiwan¶
Taiwan (ROC) maintains the same historical claims as mainland China—a legacy of the pre-1949 Republic of China government. Taiwan occupies Itu Aba (Taiping Island), the largest naturally occurring island in the Spratlys.
Strategic Importance¶
Trade Routes¶
The South China Sea’s economic importance is immense:
- Approximately $3.4 trillion in trade passes through annually
- Over 25% of global maritime trade
- Critical shipping lanes for East Asian economies
- Primary route for Middle Eastern oil to China, Japan, and South Korea
Disruption would devastate global supply chains and energy markets.
Resources¶
The seabed contains significant resources:
- Oil and gas: Estimates range from modest to enormous; exploration remains limited due to disputes
- Fisheries: Among the world’s most productive, supporting millions of livelihoods
- Seabed minerals: Potentially valuable deposits
Resource competition adds economic stakes to strategic rivalry.
Military Geography¶
For China, the South China Sea is a defensive buffer:
- Submarines can operate from its depths, complicating American anti-submarine warfare
- Distance from the Chinese coast provides warning time against attack
- Control would push American forces back from China’s periphery
For the United States, freedom of navigation in the South China Sea:
- Enables power projection throughout Asia
- Reassures allies of American commitment
- Prevents Chinese regional hegemony
China’s Strategy¶
Island Building¶
Since 2013, China has transformed reefs into artificial islands:
- Dredging sand to create land on submerged features
- Constructing airstrips, harbors, and military facilities
- Installing radar, missile systems, and aircraft hangars
- Creating “facts on the water” that change the strategic landscape
The Fiery Cross, Subi, and Mischief reefs now host substantial military infrastructure.
Coast Guard Assertiveness¶
China has deployed coast guard vessels to enforce its claims:
- Blocking Philippine resupply missions to outposts
- Confronting Vietnamese fishing vessels
- Shadowing American naval operations
- Using water cannons and aggressive maneuvers
The coast guard operates in a gray zone—less escalatory than military action but effectively asserting control.
Salami Tactics¶
China has pursued incremental gains that individually seem too small to warrant strong response:
- Seizing Scarborough Shoal from Philippine control (2012)
- Declaring an Air Defense Identification Zone over portions of the sea
- Deploying oil rigs in disputed waters
- Gradually expanding presence on contested features
Each step changes the status quo slightly; cumulatively, they transform the strategic environment.
American Response¶
Freedom of Navigation Operations¶
The US Navy conducts regular “FONOPs” to challenge Chinese claims:
- Sailing warships through waters China claims
- Asserting that international law permits transit
- Demonstrating that Chinese claims do not alter legal status
China condemns these operations as provocative; the US considers them essential.
Alliance Support¶
The United States has strengthened relationships with regional states:
- Enhanced defense cooperation with the Philippines (despite fluctuations)
- Closer ties with Vietnam (a former adversary)
- Quadrilateral coordination with Japan, Australia, and India
- Arms sales and military assistance throughout the region
Strategic Ambiguity¶
American policy on South China Sea disputes has been deliberately ambiguous:
- The US takes no position on sovereignty over features
- The US insists on freedom of navigation and peaceful resolution
- The US defense treaty with the Philippines covers armed attacks—but its application to disputed features is unclear
This ambiguity provides flexibility but may also create uncertainty that China exploits.
Regional Responses¶
ASEAN¶
The Association of Southeast Asian Nations has struggled to present a unified response:
- China’s economic leverage divides members
- Cambodia and Laos often block anti-China consensus
- Negotiations on a Code of Conduct have dragged for decades
- Individual states pursue bilateral deals with Beijing
ASEAN unity remains elusive.
Individual Strategies¶
Southeast Asian states have adopted varied approaches:
- Philippines: Oscillated between confrontation (Aquino) and accommodation (Duterte) before returning to closer US ties
- Vietnam: Maintained firm resistance while developing military capabilities
- Malaysia: Pursued quiet diplomacy while building its own presence
- Indonesia: Denied having disputes with China while strengthening defenses
No state has found an effective counter to Chinese pressure.
Scenarios¶
Confrontation¶
Risks of military confrontation exist:
- Accidents or incidents between Chinese and American forces
- Chinese seizure of a Philippine-occupied feature
- Taiwanese contingency that spills into the South China Sea
- Escalation from coast guard clashes
The region’s strategic importance means that conflict here could escalate rapidly.
Accommodation¶
Alternatively, the region could evolve toward Chinese dominance:
- American withdrawal or reduced commitment
- Regional states accommodating Chinese preferences
- De facto Chinese control despite lack of legal recognition
- “Finlandization” of Southeast Asia
Managed Competition¶
The most likely near-term outcome is continued competition:
- Ongoing Chinese pressure and American resistance
- Neither side achieving decisive advantage
- Periodic crises managed short of war
- Gradual erosion of rules-based order
Conclusion¶
The South China Sea is where the fundamental questions of 21st-century geopolitics are being answered:
- Will China achieve regional hegemony?
- Will the United States maintain its Asian commitments?
- Can international law constrain great power behavior?
- Will the nations of Southeast Asia retain genuine sovereignty?
The artificial islands rising from once-submerged reefs are monuments to Chinese ambition and symbols of the challenge facing the existing order. How the competition over these waters unfolds will shape the future of Asia—and by extension, the world.
Understanding the South China Sea is essential for anyone seeking to comprehend contemporary geopolitics. The strategic dynamics at play here—great power competition, territorial disputes, resource rivalry, alliance management—are the dynamics that will define international relations for decades to come.