Arizona constitution
Article 15
Section 1

A. No member of the corporation commission shall hold that office for more than two consecutive terms. No corporation commissioner may serve again in that office until out of office for one full term. Any person who serves one half or more of a term shall be considered to have served one term for purposes of this section.
B. A corporation commission is hereby created to be composed of five persons who shall be elected at the general election, and whose term of office shall be four years, and who shall maintain their chief office at the state capital. The two additional commission members shall be elected at the 2002 general election for initial two-year terms beginning on the first Monday in January, 2003. Thereafter, all terms shall be four-year terms.
C. In case of vacancy in the office, the governor shall appoint a commissioner to fill the vacancy. The appointed commissioner shall fill the vacancy until a commissioner shall be elected at a general election as provided by law, and shall qualify. The qualifications of commissioners may be prescribed by law.