SDCL § 11-9-39.1: State pledge not to alter rights vested in bondholders until bonds fully discharged.

The State of South Dakota does hereby pledge to and agree with the holders of any bonds issued under this chapter that the state will not alter the rights vested in the bondholders until such bonds, together with the interest thereon, with interest on any unpaid installments of interest, and all costs and expenses in connection with any action or proceeding by or on behalf of such holders, are fully met and discharged.