The oath of office of the president of the United States is the oath or affirmation that the president of the United States takes upon assuming office. The wording of the oath is specified in Article II, Section One, Clause 8, of the United States Constitution, and a new president must take it before exercising or carrying out any official powers or duties.
Lyndon Johnson being sworn in as next president, two hours after President John F. Kennedy's assassination
Franklin D. Roosevelt being administered the oath of office by Chief Justice Charles Evans Hughes on March 4, 1933, the first of Roosevelt's four presidential inaugurations.
George H. W. Bush being administered the oath of office by Chief Justice William Rehnquist on January 20, 1989.
Barack Obama being administered the oath of office by Chief Justice John Roberts for the second time, on January 21, 2009.
Between 73 and 79 days after the presidential election, the president-elect of the United States is inaugurated as president by taking the presidential oath of office. The inauguration takes place for each new presidential term, even if the president is continuing in office for a second term.
Presidential inauguration at the western front of the U.S. Capitol facing the National Mall (site since Reagan in 1981) – Joe Biden, January 20, 2021
Presidential inauguration with old overhead ceremonial porch at the eastern front of the U.S. Capitol (Lyndon B. Johnson, January 20, 1965)
Second inauguration of Theodore Roosevelt, 1905
President Reagan being sworn in for his second term "privately" on television, January 20, 1985