Senior administration officials worried about Trump's mental fitness for the presidency almost immediately after seeing him on the job, and cabinet officials held tentative discussions "within months" of him taking office to consider invoking the constitutional mechanism for replacing him, according to a excerpts from The Divider: Trump in the White House, 2017-2021 published by The Guardian.
“I think there’s something wrong with [Trump]," one senior official told authors Peter Baker and Susan Glasser. "He doesn’t listen to anybody, and he feels like he shouldn’t. He just doesn’t care what other people say and think. I’ve never seen anything like it.”
Ultimately, they determined that Trump would refuse to be removed and decided the effort was not worth the cost, although they again discussed the possibility more seriously at the end of his presidency, after he incited his supporters to attack the U.S. Capitol in a last-ditch effort to remain in power.