Immanuel Wallerstein would probably explain the rise of China – or the decline of old powers such as Spain, Portugal or even Greece – with the existence of a semiperiphery together with the core states, placed in an exploitative relationship with the periphery. According to Wallerstein, asymmetric relations are maintained because states belonging to the semiperiphery wish them to be, and these same states have the potential to become new world leaders (new core states).