The terms of the President and Vice President shall end at noon on the 20th Day of January, and the terms of senators and representatives at noon on the 3rd day of January, of the years in which such terms would have ended if this article had not been ratified; and the terms of their successors shall then begin...

Ratification

Amendment 20 was passed by Congress on March 2, 1932, and ratified on January 23, 1933:

The 1933 “Norris Lame Duck” Amendment [named after Nebraska Senator George W. Norris], as it was popularly known at the time of its ratification, eliminates the December to March Congressional “lame duck” short sessions that resulted from constitutionally and legislatively established dates for the beginning (December) and close (March in odd numbered years) of congressional sessions. The March date reflected the time required to journey to Washington before railroads shortened travel time. Sessions beginning in December of the even years lasted only three months. Congressmen elected in those years did not take office for thirteen months, and those whom they had defeated continued service in the short session. The Sessions, marked by obstructionist filibusters, were unproductive, and in light of change in travel and communications, became obsolete…