South dakota constitution
Article V: judicial department
Section 7

Retention of each Supreme Court justice shall, in the manner provided by law, be subject to approval or rejection on a nonpolitical ballot at the first general election following the expiration of three years from the date of his appointment. Thereafter, each Supreme Court justice shall be subject to approval or rejection in like manner every eighth year. All incumbent Supreme Court justices at the time of the effective date of this amendment shall be subject to a retention election in the general election in the year in which their respective existing terms expire.