Regionalism has passed through several phases since 1900. The new regionalisms that emerged in the 1990s were forms of multilateral cooperation compatible with globalism rather than antagonistic to it, and encouraged the development of inter-regionalism. The period of relative peace and prosperity after 1991 has given way since the financial crash to a period of uncertainty and increasing conflict, and the assertion of national interests. Some regionalist projects are in danger of foundering or becoming defensive and protectionist. The Trump presidency and the rise of populist nationalism has clouded the prospects for international cooperation in global governance and the maintenance of a rules-based, liberal international order. The open regionalism of the 1990s was tied to a globalist project and the provision of goods by a hegemonic power. In a world without a hegemon and with a culturally divided and fragmenting West and increasing rivalry between trade blocs the future for open regionalism is in doubt. Regionalism is being re-made and is become increasingly diverse in response to continuing economic turbulence and political upheaval.