Why China is Being Assertive in the South China Sea

Cyberwatch UNLTD
Aug 19
3 min read

Updated: Aug 19

Source: https://www.youtube.com/@taiwan_talks

The root causes of China's assertive actions in the South China Sea stem from a mix of strategic, economic, nationalist, and legal factors.

Here's a breakdown of why China is so active in this region—and why its approach can sometimes be perceived as aggressive:

1. Territorial Claims & "Historic Rights"

China asserts control over nearly the entire South China Sea using the "Nine-Dash Line", a boundary rooted in historical maps rather than modern international law. This claim overlaps with the Exclusive Economic Zones (EEZs) of several Southeast Asian nations, including Indonesia, the Philippines, Vietnam, Malaysia, and Brunei.

In 2016, an international tribunal under the UN Convention on the Law of the Sea (UNCLOS) ruled that China's claim lacks legal grounding.

China rejected the ruling, arguing that it was politically motivated, and continues to maintain its own version of maritime boundaries, which it sees as consistent with historical rights.

2. Strategic Military Importance

The South China Sea is a vital maritime chokepoint:

Around 1/3 of global shipping (worth $3–5 trillion annually) passes through the region.
It provides access to deep-water routes and is close to key military bases.

China has militarized several artificial islands, including those in the Spratly Islands, installing runways, radar systems, and missile defense systems.

For China, controlling this area is about:

Buffering U.S. naval influence.
Projecting military power beyond its shores.
Securing its maritime interests, particularly in case of regional conflicts, such as over Taiwan.

3. Natural Resources

The South China Sea is believed to have vast oil, natural gas, and fisheries resources.

China’s push for control over the region is partly driven by a desire for resource security to support its growing economy. With domestic fish stocks depleting, Chinese fishing vessels, often escorted by coast guard ships, regularly operate in areas claimed by other nations, sometimes without authorization.

4. Nationalism & Domestic Politics

Nationalism plays a crucial role in China’s maritime actions. The Chinese leadership uses strong claims over the South China Sea to reinforce its legitimacy at home.

"Defending China’s sovereignty" is a message that resonates deeply with the public, and the Communist Party cannot afford to appear weak—especially in disputes involving countries like the Philippines and Vietnam, and particularly when the U.S. is involved.

Therefore, assertive maritime posturing, while sometimes risky, serves as a way for Xi Jinping to project strength and maintain domestic support.

5. Gray-Zone Strategy

China frequently employs gray-zone tactics, which are coercive actions that are not overtly violent but still put pressure on other parties. These include:

Coast guard and militia "swarming" operations
Dangerous maneuvers near foreign ships
Harassment of resupply or patrol missions

This strategy allows China to expand its influence and test foreign responses without crossing the threshold of outright armed conflict.

Summary: Why China is Assertive in the South China Sea

Factor	Explanation
Territorial Ambition	Claims ~90% of the sea based on historical rights, despite legal opposition.
Strategic Control	Vital for military projection and regional influence.
Natural Resources	Aimed at securing oil, gas, and fisheries to support China's economy.
Nationalism	Assertive policy bolsters domestic support and strengthens Party legitimacy.
Geopolitical Signaling	Pushes back against U.S. alliances and naval presence in the region.

If this pattern continues, regional tensions could escalate. Already, countries like the Philippines are responding more assertively, while allies such as the U.S., Australia, and Japan are coordinating actions in response to China’s moves.

Conclusion:

While China’s actions in the South China Sea are driven by a combination of strategic, economic, and nationalist factors, the international community remains divided on how to engage with these claims. As tensions grow, there is a delicate balance between maintaining freedom of navigation and respecting national sovereignty. It remains to be seen how the situation will evolve, particularly if China’s assertiveness continues unchecked.