China's challenge in South China Sea is at is core a dispute over international rule of law and U.S. needs to ratify UNCLOS to have any impact on the outcome

Third, American policy makers must realize that the contest for East Asia is one of both power and law. International law supports and legitimizes the exercise of American power. It ensures that the landscape of domestic and international opinion is favorable to american objectives, policies, and actions. International law of the sea in particular, through its assurances of freedom of navigation for security as well as commercial purposes, supports the continued nature of East Asia as a maritime system. International law regarding the free use of international airspace operates similarly. accordingly, to ensure its future position in east asia the United States should take specific actions to defend the international legal architecture pertaining to the maritime and aerial commons. acceding to the United Nations Convention on the law of the sea and once again exercising direct leadership over the development of its rules and norms is the first and most critical step. The Department of State should also reenergize its limits in the seas series to reinforce, publicly and repeatedly, international law related to sea and airspace. a good place to begin the new series would be with a detailed assessment of why international law explicitly rejects China’s “U-shaped line” in the South China Sea as the basis for Chinese jurisdiction there. others could be written to describe why China’s east China sea continental-shelf claim misapplies international law and why China’s ADIZ unlawfully asserts jurisdiction in the airspace. My sense is that East Asian states, indeed many states around the world, are desperate for active american leadership with regard to the norms and laws that govern legitimate international action.