The twenty-fifth amendment could be used to take @realDonaldTrump out for the rest of his term.

If the VP and a majority of the cabinet were to certify Trump’s inability to carry out the duties of his office, Pence would become acting president. The next thing that would happen is that Trump would say, no, I’m able to carry out my duties, and he’d resume his office ...

... again in four days, unless the VP and the cabinet again certified Trump’s inability to carry out his duties. At that point, the matter goes to Congress, which has 21 days to affirm the Cabinet’s decision. But by then Joe Biden would be president, so there would never ...

... have to be a congressional vote (it takes 2/3 of both houses to sustain the finding of inability). In other words, the Vice President and a majority of the Cabinet could sideline Trump for the rest of his term, since there are only two weeks left in it.

All that said, I’m not hopeful that the Pence and the Cabinet would act.

For reference, here’s the text of section 4 of the 25th amendment.