The United States became the de facto central bank to the world through the dollar exchange standard, which was anchored to the gold standard until 1971. After World War II, the Bretton Woods Agreement established the U.S. dollar as the primary global reserve currency. Other countries pegged their currencies to the dollar, and the dollar, in turn, was convertible to gold at a fixed rate.
This system provided stability and confidence in international trade, with the U.S. effectively acting as the world's central banker. However, as the U.S. faced economic challenges and increasing trade deficits, maintaining the gold peg became unsustainable. In 1971, President Nixon abandoned the gold standard, severing the link between the dollar and gold.
After this, the U.S. continued to play a central role in the global economy, but the international monetary system shifted towards a more flexible exchange rate regime. The U.S. dollar retained its status as the primary reserve currency, relying on the strength and stability of the U.S. economy, further solidifying the country's position as a key player in global finance.