Missouri constitution
Article X: taxation
Section 18(e)

5. Any taxpayer or statewide elected official may bring an action under the provisions of section 23 of this article to enforce compliance with the provisions of this section. The Missouri supreme court shall have original jurisdiction to hear any challenge brought by any statewide elected official to enforce this section. In such enforcement actions, the court shall invalidate the taxes and fees which should have received a public vote as defined in subsection 1 of this section. The court shall order remedies of the amount of revenue collected in excess of the limit in this subsection as the court finds appropriate in order to allow such excess amounts to be refunded or to reduce taxes and/or fees in the future to offset the excess monies collected.