by Albin Sadar, American Thinker:

When a president and vice president take the oath of office in America, he and/or she makes a brief promise to the citizens of this country. For the president:

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. So help me God.

The oath taken by the vice president is similar, but has this notable addition: