Ken Griffin was stunned. It was March 10th and America’s markets had suddenly fallen out of love with Donald Trump. The NASDAQ index fell by 4%. Citadel, Mr Griffin’s hedge fund, had lost money in the rout. “You have to tear apart and re-examine the portfolio,” he told The Economist after markets closed. “And ask yourself in what ways we have positioned or mispositioned ourselves against the reality that the odds of a recession have gone higher.”