Passed by Congress July 6, 1965. Ratified February 10, 1967.
Article 2 Section 1 had only specified that if the President was unable to discharge his duties, the office of President "shall devolve upon the Vice President." It did not clarify whether the Vice President became the President with the full authority of the Office or the Acting President who does the President's job. The 25th Amendment clarified this. The Vice President would become President if for some reason the President was unable to discharge their duties.
The 25th Amendment only provides for the Vice President succeeding the President in case of something happening to the President. The Presidential Succession Act of 1947 supplements this and provides for a more complete order of succession to the President of the United States. (During a State of the Union Address when President, Vice President, Supreme Court Justices and Cabinet Officers are in one place, one Cabinet Officer does not attend the Address. He is the "Designated Survivor" in case something happens to the others.) Here is the order of succession:
Year | President | Vice-Presidential Successor |
1841 | William Henry Harrison | John Tyler |
1850 | Zachary Taylor | Millard Fillmore |
1865 | Abraham Lincoln | Andrew Johnson |
1881 | James A. Garfield | Chester A. Arthur |
1901 | William McKinley | Theodore Roosevelt |
1923 | Warren G. Harding | Calvin Coolidge |
1945 | Franklin D. Roosevelt |
Harry S. Truman |
1963 | John F. Kennedy | Lyndon B. Johnson |
In addition, the 25th Amendment provided for a vacancy in the Vice President's Office. If something happened to the Vice President and they could not serve out their term of office, the President would nominate a new Vice President. This nominee must receive a majority vote of both houses of Congress.
If the President is unable to discharge his duties, they can temporarily transfer those powers over to the Vice President. The President writes a declaration of his inability to the Speaker of the House and President Pro Tempore of the Senate. They will be able to resume their duties once they have contacted the Speaker of the House and the President pro tempore in writing they are capable.
Times when Presidents temporarily transferred power
What happens if the President is unable to discharge their duties? The Vice President and the majority of the President's Cabinet can inform the President pro tempore and the Speaker of the House in writing. The Vice President will then become the Acting President. When the President informs the President pro tempore of the Senate and the Speaker of the House that they are capable of resuming their duties, they will resume their duties.
The Vice President and the majority of the President's Cabinet have four days to notify the Speaker of the House and the President pro tempore if the President is still unable to perform their duties. Then Congress will decide if the President is fit or not.
Harper, T. (2016). The complete idiot's guide to the U.S. Constitution. Alpha Books, a member of Penguin Random House LLC.
Monk, L. R. (2015). The words we live by: your annotated guide to the Constitution. Hachette Books.