Minn. Stat. § 204C.18: BALLOTS; SECRECY.

Subdivision 1. Party preferences; protection of secrecy.

The election judges shall make no entry or notation in the election register or anywhere else showing the political party to which a voter belongs or for which political party the voter voted. No election judge shall knowingly permit anyone in the polling place to make such an entry or notation.

Subd. 2. Ballots; identifying marks; penalty.

No voter, election judge, or other individual shall place at any time a mark as a means of identification upon any ballot handed to or cast by a voter or upon spoiled or discarded ballots, except the initials authorized by section 204C.09. A violation of this subdivision is a gross misdemeanor.