Mo. Rev. Stat. § 115.620: Proxy voting, requirements.

Provisions for proxy voting for district committees organized under section 115.621 may be made by a political party. In the event that such provisions are not made, proxy voting shall only be allowed for legislative, congressional, senatorial, and judicial district committee meetings. In any event, a person may only serve as a proxy voter if such person is legally permitted to vote in the district in which the proxy resides.