(1) A person may not be employed in any disaster and emergency services organization established under parts 1 through 4 of this chapter who advocates 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 who 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 disaster and emergency services shall, before entering upon the person's duties, take an oath, in writing, before a person authorized to administer oaths in this state, that is substantially as follows: "I . ..., swear (or affirm) that I will support and defend The Constitution of the United States and The Constitution of the State of Montana 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 of the office on which I am about to enter. So help me, God."