President Trump's latest threat to fire Federal Reserve Chair Jerome Powell could put them on a collision course when the latter's term as head of the central bank ends on May 15. In an interview with Fox Business' Maria Bartiromo on Wednesday,  Mr. Trump said he would dismiss Powell if the policymaker stuck to his pledge of staying on as a Fed governor as long as the Department of Justice continues a  criminal probe  into ongoing building renovations at the Fed. Powell has said the