The 20th Amendment of the Constitution was ratified to reduce the amount of time lame duck Presidents and Congressmen had to push policies before the new administration and legislators took over. The amendment moved the date a President and Vice President began their terms from March 4 to January 20.
In the case of Congressmen, the date of the new term was moved up to January 3. The Constitution originally had the dates in March because it took elected officials time to put their affairs in order and travel to Washington. When the amendment was ratified on Jan. 23, 1933, however, less travel time was necessary, allowing the date to be moved up.