Q: What is the oath the president recites?
A: "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."
Those words transform citizen to president and mark the beginning of a new administration.
Franklin Pierce, in March 1853, became the only president to "affirm" instead of "swear" that he would protect and defend the Constitution. There are Internet mentions suggesting that Herbert Hoover also opted to affirm, but the Herbert Hoover Presidential Library Association in Iowa says Hoover did not repeat the oath in 1929, and simply said "I do" after it was read to him.
Q: Does the chief justice of the United States always administer the oath?
A: Traditionally, it is the chief justice who presides over the swearing-in ceremony. But there have been about a half-dozen exceptions including in 1923 and 1963.
In 1923, Vice President Calvin Coolidge took the oath of office at his father's residence in Plymouth, Vt., following the death of President Warren Harding. Coolidge's father, Col. John Coolidge, was a notary public and he administered the oath to his son.