Over the past 10 to 15 years, the South China Sea (SCS) has emerged as an arena of U.S.-China strategic competition. China’s actions in the SCS—including extensive island-building and base-construction activities at sites that it occupies in the Spratly Islands, as well as actions by its maritime forces to assert China’s claims against competing claims by regional neighbors such as the Philippines and Vietnam—have heightened concerns among U.S. observers that China is gaining effective control of the SCS, an area of strategic, political, and economic importance to the United States and its allies and partners. Actions by China’s maritime forces at the Japan-administered Senkaku Islands in the East China Sea (ECS) are another concern for U.S. observers. Chinese domination of China’s near-seas region—meaning the SCS and ECS, along with the Yellow Sea—could substantially affect U.S. strategic, political, and economic interests in the Indo-Pacific region and elsewhere.