Tensions surrounding the South China Sea have always been largely about oil and natural gas. This week, the US State Department used blunt language regarding China’s unsettling actions within Vietnam’s exclusive economic zone (EEZ), which include ongoing seismic surveys by a Chinese vessel protected by armed escorts. Under international UN rules, resources within the zone belong to Vietnam, but China’s “nine-dash line”—a vague, discredited borderline used by Beijing to claim nearly the entire sea—overlaps with it.