The US was forced to stop paying gold for its international debts in 1971, otherwise it would have not enough gold to continue. But this had little consequence because gold was not really the basis in the international currency system since the Breton Woods agreement in which the US forced everyone in the capitalist world to use the dollar as the basis for currency transaction. The Breton Woods agreement was the necessary step for things like the Marshall Plan and the IMF. In summary, the Breton Woods agreement was the piece of financial sorcery used to revive the capitalist world destroyed by WW2.