The Asian order is under strain as the People’s Republic of China has become an economic colossus with growing military might and diplomatic influence. The PRC is asserting territorial claims once considered impractical or worthless. Opposing China are Brunei, Japan, Malaysia, Philippines, and Vietnam.
Washington is not a claimant, but has sparred with the PRC over the U.S. Navy’s legal right to engage in intelligence gathering in Chinese waters. More important, America has a formal military alliance with Japan which, the president declared, covers disputed territories. Washington’s military relationship with Manila is looser, but Philippine officials are seeking a similar territorial guarantee.

The Obama administration has escalated U.S. involvement by sending American aircraft over islands reclaimed by China and discussing joint patrols with Japanese aircraft. An aerial or maritime incident could result in a dangerous confrontation.
Most of the islands or islets are intrinsically worthless and provide little security value. Maritime rights are affected, but in peacetime the difference wouldn’t matter so much; in wartime everything would depend on the capabilities of the contending navies.