who administer the oath of office to the president
Oath of office of the President of the United States While the Constitution does not mandate that anyone in particular should administer the presidential oath of office, it is typically administered by the Chief Justice. There have been several exceptions, however. George Washington was sworn into office during his first inauguration, on April 30, 1789, by Chancellor of New York Robert Livingston.[3][4] William Cranch, chief judge of the U.S. Circuit Court, administered the oath to Millard Fillmore on July 10, 1850, when he became president after the death of Zachary Taylor.[5] Upon being informed of Warren Harding's death, while visiting his family home in Plymouth Notch, Vermont, Calvin Coolidge was sworn in as president by his father, John Calvin Coolidge Sr., a notary public.[6][7] Federal Judge Sarah T. Hughes administered the oath of office to Lyndon B. Johnson aboard Air Force One after John F. Kennedy's assassination on November 22, 1963. This was the first (and to date only) time a woman administered the oath of office. Overall, the presidential oath has been administered by 15 Chief Justices (one of whom—William Howard Taft—was also a former president), one Associate Justice, four federal judges, two New York state judges, and one notary public.
Chief Justice of the United States The Chief Justice leads the business of the Supreme Court and presides over oral arguments. When the court renders an opinion, the Chief Justice—when in the majority—decides who writes the court's opinion. The Chief Justice also has significant agenda-setting power over the court's meetings. In the case of an impeachment of a President of the United States, which has occurred twice, the Chief Justice presides over the trial in the U.S. Senate. Additionally, the presidential oath of office is typically administered by the Chief Justice (although the Constitution does not assign this duty to anyone in particular).