The purpose of incardination is to ensure that no cleric is "freelance", without a clear ecclesiastical superior to whom the cleric is accountable and who in turn is responsible for the cleric.
Change of diocese
Incardination does not cease until the moment when that cleric is incardinated as a subject of another superior. An excardination from one diocese, for instance, does not become effective until the moment of incardination to another, so there is no gap during which the clergyman is not clearly answerable to a definitely determined superior.
A priest or deacon may move from diocese to diocese taking a new position, including moving to a new country, while formally still being incardinated in his original diocese, and therefore still under the supervision of his original diocese's bishops, at least formally, by canon law. For instance, a Philippine diocesan priest may be assigned to a parish in the United States for decades but still be formally incardinated in his original Philippine diocese.
Questions of civil jurisdiction can come into conflict with canon law in situations where a priest is on temporary assignment remotely while he remains incardinated to his diocese of origin. This applied in the case of a French priest involved in a car accident which killed two people, while at his temporary post in California. The question arose in a civil suit, whether the Diocese of Fresno (California) where he was working was responsible legally, although the priest remained incardinated in France. The civil court ruled that it was.[1]
Terminology
Its antonym, excardination, denotes that a member of the clergy has been freed from one jurisdiction and is transferred to another.
Both terms are derived from the Latincardo (pivot, socket, or hinge), from which the word cardinal is also derived—hence the Latin verbsincardinare (to hang on a hinge or fix) and excardinare (to unhinge or set free).
