The term of office of a commissioner shall be as follows:
At the general election in 1936, two members shall be elected for a term of two (2) years and one member for a term of four (4) years; at each biennial election thereafter, one member shall be elected for a term of two (2) years and one for a term of four (4) years, it being further provided that at the general election in 1936, the commissioner from county commissioner's district number one, shall be elected for a term of four (4) years and that the four (4) year term shall be allotted thereafter in rotation to districts number two, three, and one.
Idaho Code § 31-703