U.S. interests in China's excessive claims have broader impact on navigation rights than just in South China Seas

Some observers are concerned that China’s maritime territorial claims, particularly as shown in the map of the nine-dash line, appear to challenge to the principal that the world’s seas are to be treated under international law as international waters. If such a challenge were to gain acceptance in the SCS region, it would have broad implications for the United States and other countries not only in the SCS, but around the world, because international law is universal in application, and a challenge to a principal of international law in one part of the world, if accepted, can serve as a precedent for challenging it in other parts of the world. Overturning the principal of freedom of the seas, so that significant portions of the seas could be appropriated as national territory, would overthrow hundreds of years of international legal tradition relating to the legal status of the world’s oceans.⁵⁴

More specifically, if China’s position on whether coastal states have a right under UNCLOS to regulate the activities of foreign military forces in their EEZs were to gain greater international acceptance under international law, it could substantially affect U.S. naval operations not only in the SCS and ECS (see Figure 5 for EEZs in the SCS and ECS), but around the world, which in turn could substantially affect the ability of the United States to use its military forces to defend various U.S. interests overseas. As shown in Figure 6, significant portions of the world’s oceans are claimable as EEZs, including high-priority U.S. Navy operating areas in the Western Pacific, the Persian Gulf, and the Mediterranean Sea. The legal right of U.S. naval forces to operate freely in EEZ waters is important to their ability to perform many of their missions around the world, because many of those missions are aimed at influencing events ashore, and having to conduct operations from more than 200 miles offshore would reduce the inland reach and responsiveness of ship-based sensors, aircraft, and missiles, and make it more difficult to transport Marines and their equipment from ship to shore. Restrictions on the ability of U.S. naval forces to operate in EEZ waters could potentially require a change in U.S. military strategy or U.S. foreign policy goals.⁵⁵