President Donald Trump is likely planning to fire another one of his cabinet members because they've consistently exhibited a "fatal" flaw, according to one of the president's biographers. Journalist Michael Wolff, who has written four books about Trump, said during a new episode of "Inside Trump's Head" with co-host Hugh Dougherty, executive editor of The Daily Beast, that Trump will likely fire Secretary of State Marco Rubio because Rubio has upstaged Trump at times. Wolff said that is a "fatal" flaw in Trumpworld. “In Trumpworld, this is absolutely fatal. When you become the contrast gainer against Donald Trump, you’re finished," Wolff said. "When it begins to look like you are the person who is really in charge, you’re done."“You cannot do this around Donald Trump,” he added. “He just won’t let you. He’ll kill you — just chop off your head.”Wolff added that Rubio put himself in danger by being one of the few competent cabinet members in Trump's second term. He said Rubio is “the only guy who seems to show up for work every day and to sit down at a desk and to be capable of addressing what’s on his desk at any given time.”Wolff's comments come a day after Trump publicly floated the idea of a JD Vance and Marco Rubio ticket for the Republicans in 2028 during a dinner ceremony in the Rose Garden. The idea received a less-than-enthusiastic applause from the crowd. Other cabinet members, such as Food and Drug Administration Commissioner Marty Makary, Homeland Security Secretary Kristi Noem, and Attorney General Pam Bondi, have already departed the administration. Makary resigned on Tuesday rather than be fired by the president, according to reports. Trump fired both Noem and Bondi earlier this year. Noem was let go for making Trump look bad during a public hearing, and Bondi was fired for her handling of the Jeffrey Epstein files, reports indicate.