§ 3331. Oath of office
An individual, except the President, elected or appointed to an office of honor or profit in the civil service or uniformed services, shall take the following oath: ‘‘I, AB, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter. So help me God.’’ This section does not affect other oaths required by law.
(Pub. L. 89–554, Sept. 6, 1966, 80 Stat. 424.)USCODE 5 Title - Governement Organiziation and Employees