From diaconal reader:
I wonder what your opinion is. As a newly ordained permanent Deacon, I have been instructed that I may not assist with the distribution of Holy Communion or be allowed to preach at the Tridentine Mass because there is a question as to whether this is allowed. Ironically, i have been training priests in our Diocese who wish to learn the usus antiquior as well as permanent Deacons for Solemn High Masses for years. Additionally, i was told that the USCCB has referred this matter as a dubium to Rome. Can you confirm this is the case and when do you think we may hear on the subject? I realize that this is your speculative response.
I think a deacon is a deacon is a deacon. A deacon should do what deacons are permitted to do. (You can read more about that here.)
I think that if they have faculties to preach, they can preach. Since they are deacons, they can distribute Holy Communion.
A deacon could read the Gospel in English at the usual place during a Solemn Mass or Sung Mass and preach. Why not? Father can go sit down and attend piously. I could foresee this for a Low Mass also, if the priest can’t speak English well enough to be understood.
When the priest distributes Communion at one end of the rail (if there is one) the deacon could distribute at the other. Why not? If a priest is there, perhaps he should do it, but that is part of the ministry of the deacon now and I don’t see why he should be prevented.
Remember the document is called Summorum Pontificum and not Jurassicorum Parkorum, if you get my drift.
Furthermore, I call to mind the principle by which Catholics interpret law: odiosa restringenda. Law should be interpreted in such a way as to favor the person and interpret any restrictions on them in such a way that the restrictions themselves are restricted so as to favor the person’s rights. I think the benefit of doubt should be extended to deacons in this case. If there is a clarification in the future that says deacons cannot do x,y,z, fine.
But I’ll bet you a cheeseburger that isn’t going to happen! The point of Summorum Pontificum was decidedly not to create a frozen-in-time, fly-in-amber experience of the Church. The two Uses are to mutually enrich each other. The "organic" process of liturgical reasonable development was to be jump started. So, I’ll wager we won’t see the Commission or the Holy Father saying that a validly ordained deacon cannot preach or distribute Communion when that is useful and appropriate.