Renewed tension in the South China Sea

After months of signaling intent, the United States has finally made good on its promise to conduct a freedom of navigation patrol through the South China Sea. To little fanfare, the guided missile destroyer USLassen transited the area Tuesday, sailing within 12 nautical miles of at least two Chinese-occupied reefs. Beijing said its forces shadowed the US vessel. Chinese officials then protested the move, accusing the United States of escalating tension and of violating Chinese territorial waters.

With this minor action, Washington has concretely demonstrated that it rejects Beijing's claim that the occupied reefs mark Chinese territorial waters. The official US position is that it does not take sides on who rightly occupies or controls the South China Sea's numerous disputed reefs, islets and other terrestrial features. Therefore, sailing within 12 nautical miles was not a challenge to Chinese occupation per se. Washington took care to note that its vessels would sail close to landmasses occupied by Vietnam and the Philippines as well to demonstrate support for freedom of navigation, rather than the specific targeting of China.

The US Navy's choice of Subi reef (and Mischief reef according to some reports) for this patrol underscores this point. In the esoteric lexicon of maritime law and common practice, an island must be above water at high tide, and be either habitable, economically viable or both. An island is granted a 12-mile territorial sea, as well as a 200 nautical mile exclusive economic zone. China has expanded these particular reefs through dredging and building, asserting that they are now islands with territorial waters. But the United States argues that these are not islands but rather "artificial islands," since the reefs they occupy were previously considered low tide elevations, meaning that they were submerged at the highest high tides. If these are artificial islands, and not natural islands, then they are only granted a 500-meter (1,600-foot) safety zone, and no territoriality.

By claiming these are artificial islands, the United States asserts the right to pass as close as it wants, so long as it is beyond the 500-meter safety zone. Officially, then, the US signal is about what is really an "island," not about Chinese occupation. Of course, there is much more beneath the surface. Washington has expressed concern over China's island building and its expanded South China Sea maritime patrols. Tuesday's US patrol parallels the response to China's 2013 assertion of its expanded Air Defense Identification Zone in the East China Sea. Washington responded by dispatching two B-52 bombers to fly through the newly claimed Chinese airspace, defying China's right to assert sovereignty over what the United States classified as international airspace.

In both circumstances, the United States chose not to deploy overwhelming force but to demonstrate capability without committing excessive resources. Washington did not want to appear to be pushing Beijing into aggression but wanted to broadcast a commitment to freedom of navigation and to regional partners. By sending the large, relatively unprotected B-52s over the East China Sea and a single destroyer into the South China Sea, the United States showed that it was not afraid of a Chinese response. Washington called China's bluff, and Beijing blustered but did not escalate.

The United States has made it clear that these freedom of navigation patrols will continue. Regional allies have been calling for these patrols for years, particularly the Philippines. China has said continued incursions will lead to more concrete responses. Beijing did not want it to get to this point, even going so far as to suspend additional island building and invite US military officers aboard China's aircraft carrier, the Liaoning. Through appeasement and promises, Beijing hoped it could weaken the argument for overt US patrols.

While freedom of navigation is a longterm US strategic imperative, more immediate issues drove it to carry out the patrol. First was the increasing clamor from regional allies, who called Washington's commitment into question, noting that little concrete progress had been made in the much-touted "pivot" to Asia. Second were the ambiguous results of a meeting between Chinese President Xi Jinping and US President Barack Obama, particularly over issues of cybersecurity. For Washington, cyber is a much more immediate issue, while China's creeping expansion in the South China Sea is more manageable at the moment.

The question now is one of next steps. Neither side wants to escalate tension into crisis in the South China Sea. Both, however, have domestic and international reasons not to step back from their contradictory positions on the waters. It may not be the intentional moves that trigger a crisis, however. In 2001, the first major foreign crisis of the George W. Bush administration began with the accidental collision of a Chinese interceptor and a US surveillance aircraft. In the waters of East Asia, political and military clashes are frequently attributable to the actions of private fishing vessels, rather than overall government intent. As both sides become more assertive, the room for accidents rapidly turning into crises grows as well.