Mo. Rev. Stat. § 44.115
No person shall be employed or associated in any capacity in any organization established under sections 44.010 to 44.130 who advocates or has advocated a change by force or violence in the constitutional form of the government of the United States or in this state or the overthrow of any government in the United States by force or violence, or has been convicted of or is under indictment or information charging any subversive act against the United States. Each person who is appointed to serve in an organization for civil defense shall, before entering upon his duties, take an oath, in writing, before a person authorized to administer oaths in this state, which oath shall be substantially as follows:
"I, ______, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States and the Constitution of the state of Missouri, against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties upon which I am about to enter. And I do further swear (or affirm) that I do not advocate, nor am I a member of any political party or organization that advocates the overthrow of the government of the United States or of this state by force or violence; and that during such a time as I am a member of the (name of disaster or emergency organization), I will not advocate nor become a member of any political party or organization that advocates the overthrow of the government of the United States or of this state by force or violence."
§ 44.115, RSMo