Idaho Code § 34-1202A: Void ballot not counted.

At any bond election conducted by the state of Idaho, its agencies, institutions, political subdivisions and municipal and quasi-municipal corporations, any ballot or part of a ballot from which it is impossible to determine the elector’s choice shall be void and shall not be counted. It is hereby declared that any qualified elector casting such ballot or part of a ballot shall be deemed not to have voted at or participated in such bond election and such ballot or part of a ballot shall not be counted in determining the number of qualified electors voting at or participating in such bond election.