In Pittsburgh, leaders made a fine pledge to make the G20 “the premier forum” for co-ordinating policy for the global economy. If they are sincere the first order of business is to share power within the Brettons Woods institutions.

The World Bank and the International Monetary Fund had outlived their two original mandates by the 1970s. The first – financing postwar reconstruction – had been successfully completed. The other – managing balanced current accounts and fixed exchange rates – failed with the Bretton Woods system.

They have since remade themselves as the world's most powerful development agencies. Though they represent only a small part of financial flows to poor states, their imprimatur is the key that unlocks wider official aid and private capital markets. The IMF's change is the most dramatic: its purpose is to assist with balance of payments needs, but its conditions on economic policies takes it deep into the territory of domestic politics.