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.
This clause is one of three oath or affirmation clauses in the Constitution, but it is the only one that actually specifies the words that must be spoken. Article I, Section 3 requires Senators, when sitting to try impeachments, to be "on Oath or Affirmation." Article VI, Clause 3, similarly requires the persons specified therein to "be bound by oath or affirmation, to support this Constitution." The presidential oath requires much more than that general oath of allegiance and fidelity. This clause enjoins the new president to swear or affirm: "I will to the best of my ability, preserve, protect and defend the Constitution of the United States."[1]