This report considers potential implications for U.S.-China relations. China's actions for asserting and defending its maritime territorial and exclusive economic zone (EEZ) claims in the East China (ECS) and South China Sea (SCS), particularly since late 2013, have heightened concerns among observers that ongoing disputes over these waters and some of the islands within them could lead to a crisis or conflict between China and a neighboring country such as Japan, the Philippines, or Vietnam.