On the eve of the annual Association of South East Asian Nations (ASEAN) summit this week, an old issue has resurfaced: conflicting claims over the Spratly Islands. The issue is back in the news for good reason; it never really went away.

According to press reports, last week the Chinese vice foreign minister summoned the charge d' affaires from the Philippines embassy to register a "stern protest" over a new Philippines' law formally staking claim to what it calls the "Kalayaan Islands." The Chinese, of course, contend that they hold, in the words of the foreign ministry, "indisputable sovereignty over these islands and their adjacent waters."

China's Unreasonable Claim

There is nothing simple about this dispute. Taiwan and Vietnam claim all of the Spratly Islands. And the specific Bruneian and Malaysian claims overlap those of the Philippines. But it is the Chinese claim--because of its aggressive scope, the history behind it, and China's growing military capacity to back it up--that pose the real problem to regional stability.

The Chinese claim is expansive, to say the least. The Kalayaan Islands are 1,000 nautical miles away from China. By contrast, the Philippines' province of Palawan is roughly 230 miles away. (Incidentally, the Kalayaans are a municipality of Palawan.) Yet China also claims territory even closer to Palawan Island: Mischief Reef, the source of so much diplomatic scuffling 10 years ago, is only 135 miles away.

The distance between China and the territory it is claiming is apparently of no concern to Beijing. Indeed, the Chinese claim not only the Spratlys but 80 percent of the South China Sea. In support of such a massive claim, the Chinese reference 2,000-year-old maps and an imaginative reading of the Law of the Sea Treaty. Critically, the claim is passively supported by China's growing military prowess (double-digit annual growth in military spending and an expanding fleet of sophisticated warships and submarines) and what increasingly appears to be deliberate ambiguity about the intentions behind this buildup.

Highlighting Chinese Ambitions

The Philippines has done the world a great favor by reminding it of Chinese ambitions. The dispute over the South China Sea flared in the mid-to-late 1990s as a result of Chinese efforts to physically fortify their claim to Mischief Reef. Although initially alarmed by China's moves, by 2002 ASEAN was heralding a new era that would essentially set sovereign disputes aside and focus instead on mutual development. This is ASEAN's comfort zone; they were pleased to paper over the problem. But the excessive Chinese claim on the territory of their member states was never withdrawn. And neither were the structures on Mischief Reef that precipitated the crisis.

The Congress and President of the Philippines are staking their claim to the Spratly Islands without apology. They appear prepared to weather Chinese protests. Indeed, there is no cause for them to capitulate. As is, choosing among several draft bills asserting their claim and political pressure to be aggressive, the Philippines settled on a course that was the least objectionable to their neighbors.

This is a diplomatic problem. The possibility that this dispute could escalate to a point where the U.S. could be called to invoke its treaty obligations to the Philippines is remote. It did not reach that point in the mid-1990s--a much more contentious environment than today. But the risk of serious conflict only increases with time.

American Support Needed

One of the greatest values of American security treaties in peacetime, in this case the U.S.-Philippines 1951 Mutual Defense Treaty, is that they clearly show where American loyalties lie.

The United States should unequivocally support the right of the Philippines to stake its claims in the South China Sea. It should also bring attention to the responsible, deliberative, legal nature of its claims. And although it cannot support any party's particular claim, the U.S. can certainly point out the aggressive, unreasonable nature of the Chinese claim. All legalities aside, at some level, any claim to territory should have to pass a common sense test. Claiming sovereignty over 648,000 square miles of sea bordering on eight countries is absolutely untenable. And the U.S. ought to say so.

Ultimately, the U.S. cannot remain neutral in a dispute between an ally and its competition for regional influence--China. If an alliance does not at least mean dispensing with neutrality in choosing your friends, then what does it mean? Playing on the ambiguities in the American position and on weaknesses plaguing perceptions of its commitment to the region, the Chinese are content to slowly turn up the heat on the South China Sea. Silence abets their aspirations.

The Spratly Islands dispute is not just the Philippines' problem. It is an even bigger problem for the United States and all who rely on American leadership in the Asia Pacific. Left unchallenged, the Chinese claim to the South China Sea could one day leave the American Pacific Fleet asking Chinese permission to conduct routine operations. If the Chinese claims calcify at a pace similar to the development of their navy, in another 10 years, the U.S. will have a real crisis on its hands.

Walter Lohman is Director of The Heritage Foundation's Asian Studies Center.