Inside the International Contest Over the Most Important Waterway In the World

Two years ago, this disputed reef in the South China Sea was little more than a couple of rocks and a tiny weather station. Then China dug in. Now it has a running track, basketball courts–and a runway that can handle military jets.

In the South China Sea, near the reefs known as Mischief and North Danger, a detachment of seven Philippine soldiers and seven dogs guard a coral-fringed sandbar. The cay is called Flat Island, but the “island” part is a bit misleading.

A leisurely stroll around the second smallest islet of the Spratlys–a scattering of rocks, reefs, shoals and islands flung across the South China Sea–takes just minutes. Since the Philippine navy sends fresh water, fuel and other provisions only once every two months, the soldiers must survive on their spearfishing catch and filched seagull eggs. “It’s a beach resort,” says Corporal Ariel Lego, “with no resort.”

Flat Island is too hot, too salty and too small to sustain human life. Yet this spit of sand outfitted with nothing more than a pair of concrete garrisons and a wooden hut is claimed by four governments: China’s, Vietnam’s, Taiwan’s and that of the Philippines, which occupies it.

on May 10, a U.S. guided-missile destroyer cruised past Fiery Cross Reef, another disputed Spratly feature. Once just two rocks jutting out at high tide, the shoal has been transformed into a 680-acre (275 hectare) landmass, one of seven artificial islands the Chinese have constructed in the South China Sea since 2014. Passing within 12 nautical miles of Fiery Cross, the U.S.S. William P. Lawrence engaged in what the Pentagon terms a “freedom-of-navigation operation [to] challenge excessive maritime claims.” Beijing responded by scrambling fighter jets, protesting that the U.S. warship had “illegally entered waters near the relevant reef … and jeopardized regional peace and stability.” An op-ed in the state-run China Daily warned that “the moves by the U.S. in the South China Sea smack of its arrogance as the world’s sole superpower.”

The South China Sea ranks as one of the world’s most strategically vital maritime spaces–and one of its most contested. More than $5 trillion in trade flows through its waters each year, one-third of all global maritime commerce. The Strait of Malacca, the choke point that links the Indian and Pacific oceans at the southern end of the South China Sea, handles four times as much oil as the better-known Suez Canal. In an era when the world is ever hungrier for seafood, the South China Sea teems with at least one-tenth of the worldwide fishing stock; its azure depths boast untapped oil and natural-gas deposits. No wonder six governments–those of China, Vietnam, the Philippines, Taiwan, Malaysia and Brunei–have laid competing claims to various pinpricks of territory in the 3.5 million-sq.-km. waterway.

A Cold War–style showdown is now coalescing in the South China Sea, between the world’s established superpower and its presumptive one. While the U.S. is not a claimant to the sea’s specks of land, America’s navy and merchants have long cruised its waters freely. Washington contends that it is keeping vital sea-lanes safe and open for everyone. A rising China, meanwhile, is more assertively pursuing what it considers its birthright: a Monroe Doctrine–like sway over nearly the entire South China Sea and indisputable sovereignty over its sprinkling of reefs, rocks and isles.

In May, a Pentagon report noted that Chinese dredgers have reclaimed at least 3,200 acres (1,295 hectares) in the Spratlys over the past couple of years. (All the other claimants combined reclaimed just 50 acres, or 20 hectares, over the same period.) A “Great Wall of Sand” is what Admiral Harry Harris Jr., head of the U.S. Pacific Command, has dubbed the Chinese building spree. “In my opinion, China is clearly militarizing the South China Sea” …

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