President Donald Trump intensified his feud with Senator Elizabeth Warren on Thursday, telling reporters in the Oval Office that the Massachusetts Democrat “has to take a drug test” and labeling her “a liar” and “nut job.” The president, who again used the nickname “Pocahontas,” also blamed Warren for banking regulations he said forced some Midwestern lenders to close. Trump’s remarks followed a fresh challenge from Warren. Earlier in the day, she and Senator Ron Wyden wrote to Cantor Fitzgerald Chairman Brandon Lutnick seeking information on reports that the Wall Street firm was preparing a product allowing clients to bet on whether Trump-era tariffs would be overturned in court. The senators said the plan raises potential conflicts of interest because Lutnick’s father, Commerce Secretary Howard Lutnick, helped craft the duties. The lawmakers asked Cantor Fitzgerald to detail by Aug. 27 any contacts the firm has had with the White House or Commerce Department about tariffs, refunds or related litigation. A company spokesperson denied the allegations, saying Cantor “is not in the business of positioning any risk” tied to the legality of tariffs. The tariffs, which include duties of up to 145% on a range of Chinese imports, remain in force while the administration appeals a recent loss at the U.S. Court of International Trade. Warren has not publicly responded to Trump’s latest broadside, underscoring the escalating hostilities between the White House and congressional Democrats over trade policy and ethics.