The 20th Amendment
(Lame Duck Amendment)
The terms of the President and Vice President end at noon on the 20th day of January now according to the 20th Amendment Ratified on January 23, 1993.
The Congress assembles at least once every year, and the meeting begins at noon on the 3d day of January, unless they, by law, appoint a different day.
If, at the time fixed for the beginning of the term of the President, the President elect shall have died, the Vice President elect shall become President (The Vice-President is next in line to the presidency)
The Twentieth Amendment eliminated the so called lame duck sessions of Congress. National elections were held in November, but the president and the new Congress did not take office until March 4 of the next year. Defeated officials, called "lame ducks," remained in office for four months but they were soon to leave.