“Before he enter on the execution of his office, he 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.*
“* Unless, you know, 224 years from now, whoever happens to president simply decides he really doesn’t want to do that.”
The Founders set the course in a simple, concise, 35-word affirmation — the president’s top job is to “preserve, protect and defend” the Constitution. The chief executive does, of course, have other responsibilities, but his guardianship of the document they had just written was deemed by the Founders to be of such great import that they made him swear it — aloud, in front of witnesses.
In 1884, Congress, having no set oath of office, wrote its own: “I 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 …”
source : www.washingtontimes.com