Okay… funny and disturbing.
Pres. Trump shot down their attempt to get him with the 25th amendment this time… but they want to set up a Congressional committee that gives them the power to make the a determination of capability to hold office and also determine line of succession if the President is incapacitated. The succession is already determined by a letter the President creates upon taking office with new administration and after changes to the administration. So the D's are lying about the line of succession not being set in writing and used past events like Pres. Kennedy's assassination as example. It almost seems they know they are losing but are preparing for a future event they can take advantage of.
https://www.youtube.com/watch?v=ds-M6j6jFLA