The president of the United States has, legally speaking, a ton of power. He can fire the head of the country’s federal investigative agency. He can decide, unilaterally, to give ultra-classified information to foreign leaders. He has essentially unconstrained authority to use nuclear weapons however he sees fit.But what if the president’s closest advisers were to conclude he was unfit for office?According to former Deputy FBI Director Andrew McCabe, Deputy Attorney General Rod Rosenstein briefly discussed just that possibility in 2017, in the days after President Donald Trump fired FBI director James Comey.Specifically, that’s Section 4 of the 25th Amendment to the Constitution. The amendment states that if, for whatever reason, the vice president and a majority of sitting Cabinet secretaries decide that the president is “unable to discharge the powers and duties of his office,” they can simply put that down in writing and send it to two people — the speaker of the House and the Senate’s president pro tempore.Then the vice president would immediately become “acting president,” and take over all the president’s powers.Let that sink in — one vice president and any eight Cabinet officers can, theoretically, decide to knock the president out of power at any time.If the president wants to dispute this move, he can, but then it would be up to Congress to settle the matter with a vote. A two-thirds majority in both houses would be necessary to keep the vice president in charge. If that threshold isn’t reached, the president would regain his powers.Section 4 of the 25th Amendment has never been invoked in reality, though it’s a staple of thriller fiction. But there’s been a surge of interest in it throughout Trump’s presidency, as reports of the president’s bizarre behavior behind closed doors have piled up, and as his top officials have kept anonymously telling reporters that he’s unfit to govern.
Source: The 25th Amendment, explained: how a president can be declared unfit to serve – Vox