Wall Street trader Demian Reidel was euphoric on the night of Nov. 19, jumping up and down and pumping his fist in the air at Javier Milei’s campaign headquarters in a downtown Buenos Aires hotel. “We won!” he yelled. “My president!”

Less than a week later, Reidel would turn down Milei’s offer to lead the central bank and opt to fly home to Miami, dismayed at seeing the president-elect ditch key pillars of his radical economic platform.