Contending regionalisms: hubs and challengers in the Americas and the Asia-Pacific

As regions become more institutionalized, they are characterized by two competing trends. First, key regional institutions can become hub institutions that act as transmitters of a comprehensive set of norms. Second, as regional institutions increase in number, regions themselves are liable to become more fragmented. How these trends have played out is explored in two key regions, the Americas and the Asia-Pacific. It is concluded that regions are not static entities but are ever-changing structural arrangements. Hub institutions can be challenged and the consequences can be significant as regions gain in importance on the international stage.