South dakota constitution
Article XIII: public indebtedness
Section 4

Provided, further, that no county, municipal corporation, civil township, district or subdivision shall be included within such district or subdivision without a majority vote in favor thereof of the electors of the county, municipal corporation, civil township, district or other subdivision, as the case may be, which is proposed to be included therein, and no such debt shall ever be incurred for any of the purposes in this section provided, unless authorized by a vote in favor thereof by a majority of the electors of such county, municipal corporation, civil township, district or subdivision incurring the same.