Our Date to Inaugurate
When Jan. 20 falls on a Sunday, which is the case in 2013, the president is inaugurated in a private ceremony on Jan. 20, and a public inauguration follows on Jan. 21.
Until the Twentieth Amendment was ratified in 1933, Inauguration Day was held on March 4, not January 20. Although the U.S. Constitution did not mention a specific a start date for presidential terms, our founding fathers intended for the first President to assume power on the day the Constitution went into effect, March 4, 1789.
A Bumpy Start
But the first inauguration didn't occur on time. A particularly harsh winter made travel difficult for congressmen expected in New York to count votes. The count wasn't completed until April 6, and the ceremony to swear in George Washington (who still needed time to make the trip from his home in Virginia) and John Adams didn't take place until April 30.
Election of 1800
Four years after the confusing election of 1800, the Twelfth Amendment was ratified. It amended Article II, Section 1 and reformed the way the Electoral College elected the president and vice president. The Twelfth Amendment is also significant because it contained the first mention of March 4 as the day a new administration must take office.
The System Goes Afoul
Under the system created by the Constitution and the Twelfth Amendment, a President voted out of office in November would not have to leave office until the following March while congressmen voted out in November wouldn't be required to leave office until the following December.
While this long layover may have been needed in the 18th century, improved communication and transportation shortened the time needed for electors to certify elections and for administrations to transfer power.
The 20th Amendment
The Twentieth Amendment, sometimes called the Lame Duck Amendment, was introduced to amend the Twelfth Amendment and shorten the time an outgoing President and member of Congress could be a "lame duck" -that is, a public official who continues to serve after an election and before a successor's assumption of office.
The Twentieth Amendment moved the President's start date up to Jan. 20.—two weeks after the Electoral College's votes are certified by the president of the Senate. The amendment also moved the start date for the terms of senators and representatives up to Jan. 3.