Trump has told associates he has the legal authority to fire Mueller. What is clear is that he could order the Justice Department to ax Mueller, which may result in Rosenstein's departure and would certainly intensify the uproar over the investigation. Though some in the White House have preached caution, fearing a repeat of the firestorm over Comey's firing, many in Trump's orbit — including his son Donald Trump Jr. and adviser Newt Gingrich — have deemed Mueller biased and worthy of dismissal.