What aspects of the Presidential Inauguration are mandated by the Constitution? The only inauguration element required by the United States Constitution is that the President make an oath or affirmation before that person can “enter on the Execution” of the office of the Presidency. Article II, Section 1 addresses the oath of office requirement:

Before he enter on the Execution of his Office, he shall take the following Oath or Affirmation:–“I do solemnly swear (or affirm) that I will faithfully execute the Office of President of the United States, and will to the best of my Ability, preserve, protect and defend the Constitution of the United States.”

Although not specifically required by the Constitution, the Chief Justice of the United States typically administers the oath of office.

The 20th Amendment to the Constitution provides guidelines for the beginning and ending of terms served by federal government officials, including the President, Vice President, and members of Congress. Ratified in 1933, Section 1 of the Amendment sets the date of the administration transition as January 20th:

The terms of the President and the Vice President shall end at noon on the 20th day of January, and the terms of Senators and Representatives at noon on the 3d 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.

Prior to the Amendment’s ratification, the original start date for Presidential terms was March 4th, four months after the elections were held. The 20th Amendment shortened the length of time that existed between Election Day and the start of the administration’s term in office, making the shorter transition more effective and practical in a functioning government.

For more information about today’s events, see Presidential Inauguration 2017.