Mo. Rev. Stat. § 115.625

The state committee of any established political party may, except as otherwise provided by law, call a convention of delegates to be apportioned, chosen or elected in such manner as it may prescribe for the purpose of nominating presidential electors, electing delegates to national conventions, electing members of national committees adopting or making declarations of party principles on national questions, and to do and perform any other act not inconsistent with the law.