The ballots shall be counted according to the voters' marks on them as provided in sectionsand 49.93, and not otherwise. If, for any reason, it is impossible to determine from a ballot, as marked, the choice of the voter for any office, the vote for that office shall not be counted. A ballot shall be rejected if the voter used a mark to identify the voter's ballot. The state commissioner shall, by rule adopted pursuant to chapter 17A, develop uniform definitions of what constitutes a vote.
Iowa Code § 49.98