WITH A $1 billion oil rig the size of a football field, China has literally laid down a new marker in its ambition to dominate the South China Sea — and challenged President Obama’s “rebalancing” policy in Asia, only weeks after the president’s tour of the region. The rig is about 130 miles off the coast of Vietnam, in waters that Vietnam claims as an exclusive economic zone under international law. China’s claim is more tenuous, but it is backed up with a flotilla of some 80 ships that for a week have engaged in a dangerous contest of ramming and water-hosing Vietnamese vessels.
The message of the deployment is as simple as it is provocative: The regime of Xi Jinping intends to unilaterally assert China’s sovereignty over almost all of the South China Sea without regard for the competing claims of five other countries or Mr. Obama’s newly restated commitment to uphold defense agreements with two of those nations. In that sense, the rig, like Russia’s invasion of Ukraine, is a fundamental challenge to the international order the United States has tried to preserve since the end of the Cold War.