Idaho Code § 34-304
The county clerk shall, upon receipt of a written request, such request to be received no later than twelve (12) days prior to the day of election, direct that the election judges permit one (1) person authorized by each political party, if the election is a partisan election, to be at the polling place for the purpose of challenging voters, and shall, if requested, permit any one (1) person authorized by a candidate, several candidates or political party, to be present to serve as a watcher to observe the conduct of the election. Such authorization shall be evidenced by a writing signed by the county chairman and secretary of the political party, if the election is a partisan election, or by the candidate or candidates, and filed with the county clerk. Where the issue before the electors is other than the election of officers, the clerk shall, upon receipt of a written request, such request to be received no later than twelve (12) days prior to the date of voting on the issue or issues, direct that the election judges permit one (1) pro and one (1) con person to be at the polling place for the purpose of challenging voters and to observe the conduct of the election. Such authorization shall be evidenced in writing signed by the requesting person and shall state which position relative to the issue or issues the person represents. Persons who are authorized to serve as challengers or watchers shall wear a visible name tag which includes their respective titles. A watcher is entitled to observe any activity conducted at the location at which the watcher is serving, provided however, that the watcher does not interfere with the orderly conduct of the election. If the watchers are present at the polling place when ballots are counted they shall not absent themselves until the polls are closed. A watcher serving at a central counting station may be present at any time the station is open for the purpose of processing or preparing to process election results and until the election officers complete their duties at the station. If the county clerk does not receive the list of names of those desired to be present for the purpose of either poll watching or challenging within the time prescribed above, the clerk shall not allow the presence of such persons later seeking to serve in those capacities.
Idaho Code § 34-304