From Montana Code § 13-35-218, titled “Coercion or Undue Influence of Voters,” first enacted by referendum in 1913 and still in effect:
A person who is a minister, preacher, priest, or other church officer or who is an officer of any corporation or organization, religious or otherwise, may not, other than by public speech or print, urge, persuade, or command any voter to vote or refrain from voting for or against any candidate, political party ticket, or ballot issue submitted to the people because of the person’s religious duty or the interest of any corporation, church, or other organization.
Today, this would be pretty clearly seen as an unconstitutional speech restriction, but apparently in 1913 it was seen as a good government measure. Similar laws were enacted in Nevada and Oregon around the same time.