Acting President of the United States
The Acting President of the United States is a person who temporarily acts as President when the president is unable to carry out their duties, but remains in office. The position was created by the 25th Amendment to the United States Constitution.
The Acting President possesses all Presidential powers and duties during the time of their term but does not become the President, instead serving only as Acting President. This term lasts until the President declares in writing that they are no longer unable to execute the duties of their office themselves.
To date there have been two acting Presidents. Both were Vice Presidents: