South dakota constitution
Article XIII: public indebtedness
Section 16

The state may engage in works of internal improvement, any provision in this Constitution, or limitation in § 2 of this article, to the contrary notwithstanding. The indebtedness of the state for the purposes contained in this section shall never exceed one-half of one percent of the assessed valuation of all property in this state and no such indebtedness shall be incurred nor money expended, except upon a two-thirds vote of the members elect in each branch of the Legislature.