concepts
Alexander Hamilton, in essay 27 of The Federalist (1787–88) (see Federalist Papers), commented that “all officers, legislative, executive, and judicial in each State will be bound by the sanctity of an oath [to the observance of the supreme law of the land enacted by the national government]. Thus the legislatures, courts, and magistrates, of the respective members will be incorporated into the operations of the national government as far as its just and constitutional authority extends. …” Oaths (a word derived from Teutonic and Germanic languages) have been used for many reasons throughout history to swear allegiance or fealty to a feudal lord or king, to attest to the truth of a statement, or to promise to perform an act in good faith. [Source: U.S. Constitution A to Z; Oath of Office]
oath of office
presidential duties and responsibilities