What do you call an ocean that sits atop more than 10 billion barrels of recoverable oil and 100 trillion cubic feet of natural gas, provides transit for $5.3 trillion worth of shipborne trade every year, and is bordered by a half-dozen nations with competing maritime and territorial claims? If you’re a geographer, the South China Sea.

If you’re a geostrategist, however, it’s a powder keg --and one that has been heating up dangerously over the past year. Defusing it peacefully will be a test not just of Chinese behavior, but also of the ability of China and the U.S. to accommodate each other’s legitimate interests and maintain the stability on which Asia’s economic dynamism depends.

This month, China and the U.S. traded dueling statements over a buildup of regional tensions. China said that U.S. criticism of its decision to establish a military garrison covering disputed areas of the South China Sea was “a seriously wrong signal.” That followed a tense stare-down this spring and summer involving armed vessels of the Philippines, a U.S. treaty ally, and China over one of the hundreds of reefs, shoals and islands that dot the sea.

Over the past three years, more than 20 incidents --whether ship collisions, arrests of fishermen or the cutting of cables - - have taken place between Chinese vessels and those of Vietnam, the Philippines and other countries with claims to the sea’s riches. With increased prospecting and drilling for the area’s abundant oil and natural gas resources, the tension promises to intensify.

China’s expansive and imprecise claims to most of the waters, islands and natural resources of the entire South China Sea -- which are echoed by Taiwan, the other “one China” -- rest on a mixture of hoary historical accounts and international law. The other claimants -- Brunei, Malaysia, the Philippines and Vietnam -- all base their cases on the United Nations Convention on the Law of the Sea, to which China is also a party.

Although the Philippines has suggested putting its competing claims before an international tribunal as allowed for in the convention, China has refused to do so, insisting that any resolution should come through talks between the two nations. The U.S., which is pushing for a comprehensive regional solution, has not taken a position on sovereignty issues in the South China Sea, but opposes “the use or threat of force by any claimant” and has declared that “freedom of navigation, and unimpeded lawful commerce in the South China Sea” are “a national interest.”

How to move ahead?

One of the best things the U.S. could do would be to ratify the Law of the Sea, which safeguards U.S. interests in navigation and commerce and provides a strong multilateral framework for resolving such sovereignty disputes. Some Chinese have been quick to point out the hypocrisy of the U.S. invoking a treaty that it has so far failed to accept. Indeed, if Chairman Mao were alive today, he would doubtless want to shake the hands of the 34 Republican senators who said this summer that they will vote against it. In rejecting multilateralism, they are doing exactly what China wants.

In 2002, China and the Association of Southeast Asian Nations agreed to devise a code of conduct in the South China Sea for peacefully addressing disagreements. Both sides need to take up that cause, which has seen little progress. In addition, the U.S. and China can build up their ability to avert a crisis by, for example, creating a hot line dedicated to managing maritime emergencies. They can also reduce tensions by promoting joint naval exercises in areas such as counterpiracy and disaster relief.

This fall, the U.S. will elect a new president, and China will usher in a new slate of top leaders. In that supercharged political atmosphere, tough talk by either side will play to each side’s worst instincts. To keep things calm, China will need to temper its bluster over the South China Sea and its coercive economic diplomacy, and the U.S. will need to err on the side of even-handedness. While the State Department was right to issue its Aug. 3 statement deploring the rise of tensions, it aggravated the situation by needlessly singling out Chinese actions. In its standoff with China, for example, the Philippines sent a navy warship to detain Chinese fishermen --an escalation that the Chinese have so far avoided by using maritime survey and patrol vessels, rather than the navy.

The “rebalancing” of U.S. naval forces toward Asia is a welcome development. There is a danger, though, that it could end up precipitating the tensions and conflicts that it seeks to deter, especially if it emboldens countries such as Vietnam and the Philippines to overplay their hands. Secretary of State Hillary Clinton has so far deftly navigated the South China Sea. Let’s hope she remembers -- as the Chinese captain who just ran his frigate aground off the Philippines has learned -- that these are perilous waters.

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