Mo. Rev. Stat. § 49.540
No county by the issuance and sale of the bonds shall obligate itself to pay any rent or charges for the use and occupancy for a period in excess of one year. Nor shall it obligate itself to exercise its power to levy taxes to produce the required rents for the use of the buildings for a period in excess of one year nor shall the obligation to pay rent in any year when added to all other obligations for necessary governmental functions of the county, cause the county to exceed the anticipated income provided by the county for the year's operation. The sole and only obligation of the county shall be that so long as it elects to use and occupy the building it will make the payments provided for herein. The county shall, however, have an exclusive option to continue to use and occupy the building so long as it shall make the payments herein provided for.
§ 49.540, RSMo