N.H. Rev. Stat. Ann. § 669:47

When the right of any person to vote in a caucus is challenged, he shall subscribe to the following oath or affirmation before his vote shall be received: I, __________ , do solemnly swear (or affirm) that I am a legal voter in __________ , and that I intend to vote the ticket of the party holding this caucus at the next election.