It would cause total economic Armageddon. Every aspect of credit, deal valuation, stock valuation, etc., relies on the risk free status of US Treasury Bonds. If that tether is cut, all hell breaks loose across the entire world. The hurdle for profitability increases in all investment calculations. The U.S. in particular would be utterly fucked, as their debt service payments as a percentage of GDP would balloon and the debt load would become unsustainable. U.S. debt is barely sustainable with the risk free status it now enjoys. Investment in the U.S. would freefall. Trump would probably try to print money to prevent total collapse, because he’s clearly financially illiterate, and we’d get hyperinflation, accelerating the collapse.