For most of its history, China was at the center of an East Asian interstate system, the Chinese tianxia. The Chinese word for China, Zhongguo, even means "central state" (or "middle kingdom"). By contrast, the modern interstate system is usually understood as an anarchic system of competing states. In reality, the 21st century interstate system is a central state system like the Ming Dynasty Chinese tianxia, but centered on the United States, not on China. The American-centered system began to form much earlier than is usually understood, and was clearly described by many intellectuals in the aftermath of World War One. It is now in its prime, not its decline. Like the historical Chinese tianxia, the current American Tianxia is strongly hierarchical, but unlike the Chinese tianxia, it is not relational. This calls into question the key conceit of Westphalian sovereignty, the sovereign equality of states. But it is also responsible for the relatively peaceful conduct of international relations under the American Tianxia.