Idaho Code § 50-813: Calculation for number of required signatures.

In cases where a city is operating under the council-manager plan, if there is no direct mayoral election, and a statute provides for petitions or elections based upon the total number of votes cast for mayor at the last preceding city election, the calculation of signatures or votes necessary under state law shall be based upon the total number of votes cast for the city councilman who received the highest number of votes at the last preceding city election.