When he was France’s finance minister in the 1960s, former French President Valéry Giscard d’Estaing famously complained about the “exorbitant privilege” that the dollar’s position as the world’s leading reserve currency conferred on the United States. This meant, essentially, that the US could borrow at low interest rates, run persistently large trade deficits, and print money to finance its budget deficits. He never could have imagined that the US would end up letting these advantages slip through its fingers.Since returning to the White House in January, US President Donald Trump has been systematically destroying faith in the dollar in both global financial markets and among governments and central banks. For starters, Trump has put America’s public finances on an even more unsustainable path than they were on before he took office.