According to Article II, Section 1 of the U.S. Constitution: "Before he enter on the Execution of his Office, [the President of the United States] 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.’"