When Jerome Powell was sworn in as chair of the Federal Reserve eight years ago, economists worried that inflation and interest rates were too low and that too few Americans had jobs.

Donald Trump, during his second term as president, has consistently shown us two things: He has a rapacious obsession with retribution, and he usually face-plants while seeking to punish his perceived enemies. Now, Trump may show us a third thing.

With a new Fed chair stepping in, uncertainty around inflation could rattle the market.