World trade is now a game in which the US produces dollars and the rest of the world produces things that dollars can buy. The world's interlinked economies no longer trade to capture a comparative advantage; they compete in exports to capture needed dollars to service dollar-denominated foreign debts and to accumulate dollar reserves to sustain the exchange value of their domestic currencies. To prevent speculative and manipulative attacks on their currencies, the world's central banks must acquire and hold dollar reserves in corresponding amounts to their currencies in circulation. The higher the market pressure to devalue a particular currency, the more dollar reserves its central bank must hold. This creates a built-in support for a strong dollar that in turn forces the world's central banks to acquire and hold more dollar reserves, making it stronger. This phenomenon is known as dollar hegemony, which is created by the geopolitically constructed peculiarity that critical commodities, most notably oil, are denominated in dollars. Everyone accepts dollars because dollars can buy oil. The recycling of petro-dollars is the price the US has extracted from oil-producing countries for US tolerance of the oil-exporting cartel since 1973.