This video outlines the purpose of the 25th Amendment is to remove a President that has been mentally or physically incapacitated. The Democrats apparently want to improperly use the 25th amendment to bypass the impeachment process. This in turn implies the are not feeling too good with the Mueller investigation. This short video is worth watching.
Always remember, the forefathers of the United States believed the people are the ones who decide who represents them, not the politicians.
A couple of points:
Rosenstein and McCabe are Republicans and the founding fathers actually did not believe it was the people that were best to decide who represents them in the senate and the presidency. Senators were originally elected by the state legislatures and we still elect electors to elect the president.