what does “or affirm”mean?
Laying down his receiver, Katzenbach crossed to a bookcase, opened the glass doors, and took a heavy blue volume from the lower shelf. It was the Government Printing Office's 1953 edition of the annotated Constitution, edited by Edward S. Corwin. Riffling through it, Nick put his finger on the bottom of page 384.
Back at his desk he read, "I do solemnly swear, parenthesis, or affirm, unparenthesis, that I will faithfully execute the, capital, Office of President of the United States, comma, and will to the best of my ability, comma, preserve, comma, protect and defend the Constitution of the United States period."