Beijing's Choice in the South China Sea

A U.S. Navy destroyer sailed past Subi Reef.

Photographer: DigitalGlobe/ScapeWare3d/DigitalGlobe/Getty Images

To its credit, this week's U.S. operation to challenge Chinese territorial claims in the South China Sea was measured. China has good reason to ensure its response is, too.

In the Navy's carefully calibrated mission, a guided-missile destroyer and a pair of surveillance planes passed within 12 nautical miles of two artificial islands that China has recently reclaimed from the sea. Under international law, these formerly submerged reefs have no territorial seas. By distinguishing its actions from the "innocent passage" that ships claim when moving through another nation's waters, the U.S. made clear that piling up thousands of tons of sand gives China no special claim to surrounding waters.

U.S. officials responded to reporters' queries but didn't overhype the operation. And while some critics complained that the U.S. had waited too long to act, the timing was fortuitous. Chinese leaders, preoccupied this week with a Communist Party plenum in Beijing, have thus far confined their outrage to diplomatic complaints.

QuickTake Territorial Disputes

It's important not to expect too much from this one gesture. The operation didn't contradict China's claim to sovereignty over the artificial islands; the U.S. takes no formal position on overlapping claims in the South China Sea. And there's little chance the Chinese will now suddenly halt construction of runways and other facilities with possible military uses there. Nearly two years ago, the U.S. sent a pair of B-52 bombers to challenge the air-defense identification zone China had unilaterally declared over disputed islands in the East China Sea. Dozens of airlines still respect the zone, even though the U.S. and Japan don't.

The real test of success is whether U.S. actions reinforce existing maritime law and norms. The U.S. could further that goal by now going forward with military cruises that target reefs and rocks controlled by Vietnam and the Philippines. When President Barack Obama visits Southeast Asia next month for a pair of regional summits, he should press U.S. friends and allies to clarify their own maritime claims and seek international arbitration, as the Philippines has in bringing a case at The Hague against China's expansive claims. The White House might even consider a new push to get the Senate to ratify the United Nations Convention on the Law of the Sea, so the U.S. can stand on firmer legal ground itself.

The goal is to show China that the costs of escalating are greater than any realistic benefits: It can ramp up its naval presence in the South China Sea, but that probably won't keep the U.S. away. Rapid militarization -- something that Chinese President Xi Jinping, in his recent visit to Washington, vowed not to pursue -- would only increase the risks of an unintended clash and badly exacerbate tensions with China's Southeast Asian neighbors.

China can't afford that right now. Policy makers are rightly consumed with the Herculean task of easing the economy into a slower-growth trajectory without sparking a financial crisis. The Chinese military still lags far behind that of the U.S., despite recent improvements. Stability continues to serve Chinese purposes better than conflict.

These facts appear to have persuaded Beijing to dial down tensions in the East China Sea; this weekend, Chinese Premier Li Keqiang will take part in a trilateral summit with the leaders of South Korea and Japan. China would be wise to show similar restraint further south.

To contact the senior editor responsible for Bloomberg View’s editorials: David Shipley at davidshipley@bloomberg.net.