Despite last month’s U.S. Navy operation near Chinese-occupied Mischief Reef in the South China Sea, influential commentators have offered increasingly dire warnings about the failure of U.S. policy to prevent growing Chinese dominance in the region. For instance, former Obama Administration official Ely Ratner recently warned that “time is running out to stop China’s advance” and called for the U.S. to adopt a new much more aggressive policy of deterrence. As the Trump Administration prepares its new South China Sea strategy, it is possible that elements of Ratner’s recommendations will be adopted. While I would welcome such a policy shift, I explain here that the U.S. must also be prepared for the difficult diplomatic and legal consequences of adopting this new approach.

Like other China hawks before him, Ratner argues that that the U.S. should shed “its position of neutrality” and “instead increase its efforts to help the region’s countries like Vietnam and Philippines to defend themselves against Chinese coercion.” This would take the form of selling weapons systems that improve those countries’ “counterintervention” capabilities against the Chinese. Most provocatively, Ratner recommends that the U.S. “negotiate new agreements with countries in the region to allow U.S. and other friendly forces to visit or, in some cases, be permanently stationed on their bases in the South China Sea.” This could include islands occupied by the Philippines, Vietnam, or Taiwan.

But as Ratner acknowledges, adopting his recommendations would require a significant change in U.S. policy. For decades, the U.S. has maintained a policy of neutrality on questions of territorial sovereignty in the South China Sea while focusing its efforts on maintaining international law rights to freely navigate the waters. All of the U.S. freedom of navigation operations in the region have scrupulously avoided difficult questions of sovereignty by, for instance, following the rules of innocent passage when traversing disputed territorial seas claimed by China. In that circumstance, “innocent passage” preserves U.S. navigation rights without taking sides on questions of who owns the relevant territorial seas.

Under Ratner’s “muscular deterrence” approach, the U.S. would end this policy and effectively take sides on the knotty sovereignty disputes in the South China Sea by providing weapons that would bolster the ability of Vietnam, the Philippines, and Taiwan to defend their territorial claims against China. Indeed, if the U.S. signed agreements to visit or even base U.S. armed forces on disputed South China Sea islands, it would be further confirming that it recognizes the sovereignty of those countries over those particular territories. After all, how could the Philippines have the right to invite U.S. military forces to visit or stay in a territory unless it has sovereignty over that territory?

From a policy perspective, this approach makes a lot of sense. But from a legal perspective, taking sides in sovereignty disputes will lead to serious complications. For one thing, the non-Chinese claimants often have territorial disputes with each other. One possible U.S. base identified by Ratner, Thitu Island, is controlled by the Philippines, but it is claimed by both Vietnam and Taiwan (as well as China). All four countries also have claims to Taiwan-controlled Taiping Island, which Ratner also recommended as a possible U.S. base. While U.S. support would no doubt be welcomed, these four-way sovereignty disputes are part of the reason why the Southeast Asian claimants have not been able to form a united front against China. By “shedding neutrality,” the U.S. would not just be taking sides against China but would also be taking sides against other claimants.

Moreover, stationing U.S. military forces on territory that China claims it has “indisputable sovereignty over” could be viewed as an invasion and occupation of Chinese sovereign territory. In China’s view, such an act would (technically) trigger China’s legal rights under the U.N. Charter to self-defense against an “armed attack.” A Chinese military action is not likely, but can’t be ruled out.

Putting U.S. forces on Taiping Island, controlled by Taiwan, is even more provocative because the Chinese might see that as a legal precedent for returning U.S. forces to Taiwan itself. In the past, China has suggested a U.S. military presence in Taiwan would justify Chinese military action and Taiping Island would present almost the same legal situation if U.S. troops were stationed there.

All of these complications are probably why the U.S. has maintained its policy of not taking sides in sovereignty disputes in the South China Sea. There is a way, however, for the U.S. to maintain its neutral stance while bolstering non-Chinese claimants. The U.S. could argue that its intervention into the region arises out of its opposition to all forms of coercion to resolve territorial disputes in the South China Sea. Its supply of arms would be limited to “defensive weapons” that would not support an attack by one claimant on the other. Moreover, even if it stationed troops or made agreements to visit disputed territories, it could simply say that its troops support the status quo and nothing more.

From a legal perspective, the idea that the U.S. would pledge military aid and support to countries to defend disputed territories is borderline incoherent. But there is precedent for this kind of incoherence. In the case of the Senkaku/Diaoyu Islands at the center of a dispute between Japan and China, the U.S. has declared that its defense treaty commitment to Japan extends to those disputed islands. While not recognizing Japan’s sovereignty over the Senkakus, the U.S. is committed to the defense of the status quo and opposes any use of force against that status quo.

Similarly, the U.S. commitment to assist Taiwan is not based on a recognition of Taiwan’s sovereignty, but a commitment to preventing China from using force to coerce reunification. Ratner’s recommendations would probably require the extension of this legally murky approach to the South China Sea.

There is little doubt that the U.S. needs to change strategies if it is to achieve its goal of preventing Chinese military dominance of the South China Sea. I hope Ratner’s proposals are seriously considered by the new administration. But completely abandoning neutrality on sovereignty is going to lead to difficult diplomatic and legal consequences. Any new approach needs to keep this reality in mind.