In the medium term, focusing on managing North Korea at the expense of the United States’ interests in the South China Sea could destabilize the U.S.–Chinese relationship. Such a course would suggest a dangerously narrow definition of U.S. priorities, encouraging China to more assertively press its position on other regional issues, such as its relationship with Taiwan or the territorial disputes in the East China Sea.
But it is in the long term that U.S. acquiescence in the South China Sea would be the most damaging. If the United States ceases to defend freedom of navigation, others will not make up for its absence. U.S. allies such Australia and Japan are committed to international law, but they do not have their own freedom of navigation programs, and they cannot maintain a regular military presence in the South China Sea. Similarly, if the Trump administration does not seek to rally Southeast Asian countries to support the waterway’s openness, those countries will have little reason to stand up to China on their own. States in the region, including U.S. partners, will quickly presume that Washington is pulling back from Asia and will increasingly view China as the region’s most dependable power, despite its misbehavior at sea. The result would be a tilt in Asia’s balance of power toward Beijing.
If the United States waits months to get tough in the South China Sea, it will do so from a weaker legal, military, and diplomatic position than it holds today. Making matters worse, a sudden shift after a long delay could cause whiplash in Beijing, sending the bilateral relationship into a crisis.
That is why the United States must step up now. Just as international law does not enforce itself, access to the oceans cannot be taken for granted—and it should certainly not be traded away.