Excommunicated cardinals and conclaves
An interesting but purely hypothetical question was sent my way: would an excommunicated cardinal be allowed to participate in a papal conclave?
I think it depends.
Note that excommunication may be incurred in either of two ways, latae sententiae (automatically) or ferendae sententiae (formally imposed or declared); passing over my usual appeal to abolish latae sententiae penalties, I’ll just say that the consequences of excommunication vary somewhat depending on whether the sanction was produced latae sententiae or ferendae sententiae.
Cardinals under age 80 have the right and duty to participate in a papal conclave. UDG 33, 38. Cardinals may, however, plead an “impediment” against participating in a conclave, but an impediment must be so recognized by (presumably a majority of) the cardinal electors gathered for a conclave. UDG 38.
Now, anyone laboring under a latae sententiae excommunication is forbidden to exercise ecclesiastical office or to place acts of governance. Canon 1331 § 1, 3º. An excommunicated cardinal would be able to plead, I think, an impediment against his participation in a conclave and the College could recognize such a plea and excuse his attending.
Of course, someone laboring under a latae sententiae excommunication might be doing so secretly, or the College could, I suppose, decline to recognize a latae sententiae excommunication as an impediment to participation, and in any event, the College could not, I think, bar entrance or participation on those grounds. In short, one laboring under a latae sententiae excommunication could end up casting ballots in a conclave. What then?
Not to worry: the prohibition against latae sententiae excommunicates voting goes only to the liceity, not the validity, of the ballot cast. That is not to wink at the requirements of liceity, of course, but rather, to insure that the outcome of any ecclesiastical election, including a papal election, is not impugned on those grounds.
But things change, I suggest, if the excommunication is ferendae sententiae, that is, if it were formally imposed or declared.
Canon 1331 § 2, 2º scores as invalid any attempt by one under a ferendae sententiae excommunication to exercise office or to place acts of governance. Moreover, Canon 171 states that one under a ferendae sententiae excommunication casts a null ballot in an ecclesiastical election. Indeed, if it can be determined that the outcome of the election turned on that null ballot, the election itself would be null. It seems to me, therefore, that the College could, to avoid such severe complications in its work, exclude from a conclave any cardinal laboring under a ferendae sententiae excommunication because such a prelate could not validly exercise office, place acts of governance, or cast ballots.
To our question, then, are excommunicated cardinals allowed to participate in a conclave? Answer: it depends.
Finally, if my analysis is correct, one might worry about a cardinal elector committing an excommunicable act during the conclave itself (say, directly violating the seal of confession contrary to Canon 1388). What about his continuation in the conclave?
The law, as we have seen, turns on whether one labors under a ferendae sententiae, but not simply a latae sententiae, excommunication. Now, per Canon 1405 § 1, 2º only a pope has jurisdiction to judge cardinals and to determine, therefore, whether an apparently incurred latae sententiae excommunication (such as for violating of the seal) is to be formally declared or imposed. Of course, there is no pope to judge a cardinal during a conclave, so, a cardinal elector cannot fall under a ferendae sententiae excommunication during a papal conclave.
In short, an elector under ferendae sententiae excommunication at the time of sede vacante could, I think, be barred from entering a conclave and, even if he were admitted, could not vote; any elector under a latae sententiae excommunication could plead such an impediment and be excused attending, but he could not be barred from entering on those grounds.