Answer: Impeachment
Explanation:
Congress can remove a President from office if there is a belief amongst lawmakers that the President is no longer fit to hold power.
The House of Representatives will vote to impeach the president and if a majority vote for the impeachment, the President will be impeached after which the process passes to the Senate which then holds a trial and votes on removing the President.
If two-thirds of the Senate present votes to remove the President, the President will be removed from power.