Mo. Rev. Stat. § 115.099: Authority to supervise judges.

Each election authority shall have authority to direct judges in their duties and to compel compliance with the law. Each election authority may substitute judges at his discretion on election day. Each election authority shall also have authority at any time to remove any judge for good cause and to replace the judge with a qualified person from the same political party as the removed judge. Any judge selected pursuant to this section shall be selected to ensure that no political party shall have a majority of judges at any polling place and that each major political party has at least one judge serving at the polling place.