Rules for Missouri Townships
The Missouri Constitution, in Article VII, Section 6, is direct and to the point. Officials or public employees who appoint a relative forfeit their office or job. This happens at the time the appointment is made. Appointment does not have to be to a paid position. "Any public officer or employee in this state who by virtue of his office or employment names or appoints to public office or employment any relative within the fourth degree, by consanguinity or affinity, shall thereby forfeit his office or employment."
The section forbids appointments of relatives. An official who abstains from voting when a relative is under consideration violates nothing. Also, a person is not in violation if elected to a position that a relative had previously held by election or appointment. However, if the township's operator hires his or her son to help blade roads, the operator's job is forfeited. The son keeps his job. If the board should hire the son, there is no violation. It is the use of an official position to appoint a relative that is prohibited.
Degrees of relationship
All relatives have a common ancestor. Degrees of relationship are calculated by counting from one relative back to the common ancestor, then forward to the other relative. First cousins, for example, the children of siblings, would be related in the fourth degree: from A to parent to grandparent, to B's parent to B. Sisters would be related in the second degree: from one to parent to the other.
Consanguinity and affinity
These terms are fancy ways of saying, "by blood or by marriage." A daughter and daughter-in-law count exactly the same. Spouses count as a unit, so that relatives of either are equivalent relatives of both. It is not clear if ex-relatives are or are not considered still related.