Mo. Rev. Stat. § 67.1718

In the event the proposed metropolitan district consists of only one county, if a majority of the votes cast on the proposal by the qualified voters voting thereon are in favor of the proposal, then the metropolitan district shall be deemed organized, but if a majority of the votes cast by the qualified voters voting are opposed to the proposal, then the metropolitan district shall not be deemed organized unless and until another proposal to authorize the organization of a metropolitan district is submitted to the voters of the proposed district and such proposal is approved by a majority of the qualified voters voting thereon.