It is common to hear in Catholic theology that each sacrament has an ordinary minister and, sometimes, an extraordinary minister. But what makes a minister ordinary or extraordinary?
According to AD. Tanquerey’s dogmatic theology, an ordinary minister is:
ordinarius, qui ad sacramenta ministranda ex officio specialiter consecratus vel [Cn. et] deputatus est;
Tanquerey, Synopsis Dogmaticae Theologiae, par. 405, p. 284
The ordinary [minister], who is specially consecrated or [Cn. and] deputised to minister the sacraments from his office.
My translation of Tanquerey, Synopsis Dogmaticae Theologiae, par. 405, p. 284
This seems consistent with how the phrase “ordinary minister” is used and how the role in seen in the Scriptures. The ordinary minister of a sacrament is a revealed truth (not a role created, removed, or altered by a juridical act) that a certain office is instituted by Christ for this purpose, not by being given special permission or delegation but of the office itself (ex officio).
This is unique from an extraordinary minister who is, according to Tanquerey:
extraordinarius, qui ob necessitatem vel peculiare privilegium eadem ministrat.
Tanquerey, Synopsis Dogmaticae Theologiae, par. 405, p. 284
The extraordinary [minister], who due to necessity or peculiar privilege, ministers the same things.
My translation of Tanquerey, Synopsis Dogmaticae Theologiae, par. 405, p. 284
What is unique about the extraordinary minister is that he cannot, of himself, give the sacrament but only by delegation. This is seen in the Acts of the Apostles where deacons are instituted and delegated certain responsibilities, such as baptising, such as is the case of the deacon Philip in Acts 8. However, here and elsewhere, the Sacrament of the Laying on of Hands (Confirmation) is reserved to the bishop. After the men in Samaria are baptised, the apostles (the primordial bishops) are sent and
…prayed for them, that they might receive the Holy Ghost: (For as yet he was fallen upon none of them: only they were baptized in the name of the Lord Jesus.) Then laid they their hands on them, and they received the holy Ghost.
Acts 8:15-17
The ordinary minister is always used for this Sacrament in Acts. While it can be delegated to a priest, the Scriptures are clear that it is not ex officio; it is not according to his office to give Confirmation.
Therefore, the ordinary minister is not a changeable juridical structure but a matter of doctrine regarding what each holy order is. Either the bishop alone is the ordinary minister (as is held in the West) or the bishop and priest are both the ordinary ministers (as is often held in the East). However, the attempted solution to make the ordinary minister in the West different from the ordinary Minister in the East (which I have often seen in normally faithful, orthodox Roman Catholic literature) is a plain admission of cultural relativism: this doctrine is true in the West but false in the East. Rather, truth is catholic: universal.