Chinese provocative actions in the South China Sea (SCS) have intensified U.S. and Chinese military interactions and any corresponding miscalculation could bring the two nations into direct conflict. This paper examines the tensions in this region that stem from China's rapid and large-scale land reclamation projects in the SCS and overlapping claims with U.S. allies on islands in the region. It analyzes U.S. national interests that are directly opposed to China's "Core Interests" in the SCS and that are driving diplomatic, economic and military relations. Conflicting national interests coupled with China's escalatory actions against U.S. allies and partners contributes to the current military tension between the two nations. The paper concludes that China's continued provocative actions in the SCS will be a recurring source of friction. Thus, the U.S. should maintain its presence to preserve regional security and stability. More important, the U.S. can dictate how and when to respond to Chinese provocations and the paper argues that now is the time for the U.S. to draw the proverbial line in China's man-made sand.