Here's the story behind the oath of office of the President of the United States, with a Biblical twist! The official wording goes like this:

"I do solemnly swear [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."

The Constitutional language gives the option to "affirm" instead of "swear". While the reasons for this are not documented, it may relate to certain Christians, including Quakers, who apply the scripture from James quite literally.

But above all things, my brethren, swear not, neither by heaven, neither by the earth, neither by any other oath: but let your yea be yea; and your nay, nay; lest ye fall into condemnation.

James 5:12

Franklin Pierce was the only president known to use the word "affirm" rather than "swear." Herbert Hoover is often listed to have used "affirm" as well, owing to his being a Quaker, but a newsreel taken of the ceremony indicates that the words used were "solemnly swear." Richard Nixon, who was also a Quaker, swore, rather than affirmed. Given the outcome of "tricky Dick" Nixon's presidency, we're guessing a little more attention to the oath and scripture might have made all the difference in a presidency gone bad.