"When President Franklin Delano Roosevelt and other Western leaders were starting to plan for the postwar world, they had the recent past very much in their minds in other ways. They wanted to build a robust world order that would prevent the world from sliding, yet again, into another deadly conflict. The interwar years had been unstable ones, partly because the League of Nations had not been strong enough. Key powers, the United States in particular, had not joined or, like Germany and Japan, had dropped out. This time, Roosevelt was determined that the United States should be a member of the new United Nations. He was also prepared to do a good deal to keep the Soviet Union in. What had been a precariously balanced international order was put under further strain in the 1930s by the Great Depression, which encouraged countries to turn inward, throwing up tariff walls to protect their own workers and their own industries. What may have made sense for individual nations was disastrous for the world as a whole. Trade and investment dropped off sharply and national rivalries were exacerbated. To avoid that happening again, the Allies, with the Soviet Union's grudging acquiescence, created the economic institutions known collectively as the Bretton Woods system. The World Bank, the International Monetary Fund, and the International Trade Organization (this last did not materialize as the World Trade Organization until much later) were designed to provide stability to the world's economy and to encourage free trade among nations. How much difference these all made to the international order after 1943 will always be a matter of debate, but the world did not get a repeat of the 1930s."