and in doing so they would automatically clear other nations deficits. He proposed a global bank that would issue its currencythe bancorwhich was exchangeable with national currencies at fixed rates of exchange and would become the unit of account between nations, which means it would be used to measure a country's trade deficit or trade surplus. Every country would have an overdraft facility in its bancor account at the International Clearing Union. He pointed out that surpluses lead to weak global aggregate demandcountries running surpluses exert a "negative externality" on trading partners, and posed, far more than those in deficit, a threat to global prosperity. In his 1933 Yale Review article "National Self-Sufficiency," he already highlighted the problems created by free trade. His view, supported by many economists and commentators at the time, was that creditor nations may be just as responsible as debtor nations for disequilibrium in exchanges and that both should be under an obligation to bring trade back into a state of balance. Failure for them to do so could have serious consequences. In the words of Geoffrey Crowther, then editor of The Economist, "If the economic relationships between nations are not, by one means or another, brought fairly close to balance, then there is no set of financial arrangements that can rescue the world from the impoverishing results of chaos." These ideas were informed by events prior to the Great Depression whenin the opinion of Keynes and othersinternational lending, primarily by the US, exceeded the capacity of sound investment and so got diverted into non-productive and speculative uses, which in turn invited default and a sudden stop to the process of lending. Influenced by Keynes, economics texts in the immediate post-war period put a significant emphasis on balance in trade. For example, the second edition of the popular introductory textbook, An Outline of Money, devoted the last three of its ten chapters to questions of foreign exchange management and in particular the "problem of balance". However, in more recent years, since the end of the Bretton Woods system in 1971, with the increasing influence of monetarist schools of thought in the 1980s, and particularly in the face of large sustained trade imbalances, these concernsand particularly concerns about the destabilising effects of large trade surpluseshave largely disappeared from mainstream economics discourse and Keynes's insights have slipped from view. They are receiving some attention again in the wake