Whether those who are not priests can excommunicate?

❌ Objection 1 : It would seem that those who are not priests cannot excommunicate. Because excommunication is an act of the keys, as stated in Sent. iv, D, 18. But those who are not priests have not the keys. Therefore they cannot excommunicate.

❌ Objection 2 : Further, more is required for excommunication than for absolution in the tribunal of Penance. But one who is not a priest cannot absolve in the tribunal of Penance. Neither therefore can he excommunicate.