The South China Sea

The Nine-Dash Line

China claims sovereignty over most of the South China Sea — approximately 3.5 million square kilometers — based on the 'nine-dash line,' a boundary first drawn by the Republic of China in 1947. This claim overlaps with the exclusive economic zones of Vietnam, the Philippines, Malaysia, Brunei, and Indonesia.

Why the South China Sea matters:

• Trade: Approximately $3.4 trillion in goods transit the South China Sea annually — roughly one-third of global shipping
• Resources: The seabed contains significant oil and natural gas deposits, and the waters are a major fishing ground
• Strategy: Control of the South China Sea would allow China to project military power across Southeast Asia and challenge US naval dominance in the Western Pacific

In 2016, the Permanent Court of Arbitration in The Hague ruled that China's nine-dash line has no legal basis under UNCLOS (the UN Convention on the Law of the Sea), in a case brought by the Philippines. China declared the ruling 'null and void' and has continued its activities.

Island-Building and Militarization

Beginning around 2013, China embarked on an unprecedented island-building campaign in the Spratly Islands, dredging sand and coral to create artificial islands from submerged reefs. These islands have been equipped with military infrastructure: airstrips, radar systems, anti-ship missiles, and surface-to-air missiles.

In 2015, Xi Jinping told President Obama that China would not militarize the islands. It subsequently did so extensively.

The strategic effect has been to create a network of military outposts across the South China Sea, giving China the ability to project power, monitor maritime traffic, and potentially deny access to other navies.

The US responds with 'freedom of navigation operations' (FONOPs) — sending warships through contested waters to challenge China's claims. These operations create regular flashpoints for potential escalation.