Why was the U.S. so special in the 1970s to get experimental privileges to sometimes have both kinds of Communion available?
Well, it was and it wasn't.
In its Sept. 21 news release about restricting Communion under both kinds, the Phoenix diocese mentioned "experimental privileges" given to the U.S., U.K., and Oceania from 1975 to 2005, when those privileges expired. However, that has been causing some confusion, because there were no experimental privileges regarding Communion availability that expired, said Fr. Richard Hilgartner, executive director of the Office of Divine Worship at the bishops' conference.
What did affect Communion availability was an indult.
In the late 1970s the U.S. bishops asked the Holy See for an indult (an exemption from a general requirement that is granted by a church authority) to expand possible days for Communion in both kinds to Sundays and other holy days, Hilgartner told NCR, because at the time, the Roman Missal didn't allow it.
If the U.K. and Oceania received a similar indult, they must have asked for permission as well, Hilgartner said, but he doesn’t know if they did or didn't.
In 1984, the indult was granted in the U.S., so both kinds were permitted to be available for Sundays and other holy days if the bishop of the diocese deemed it appropriate.
In 2000, the Roman Missal supplanted that indult, fitting it into the General Instruction of the Roman Missal that both kinds may be available "whenever it may seem appropriate" to the priest as outlined by the bishop of the diocese. (See the GIRM 283.)
So there was no need for an indult anymore, Hilgartner said, because it was now law. And since it's in the Roman Missal, it goes for the entire world now, not just the U.S., U.K. and Oceania.
Hilgartner added that under current law a bishop would be within his rights to restrict the availability of Communion in both kinds, because he would be following the "whenever it may seem appropriate" part of the law.
Something that did expire in 2005 was the special privilege given to extraordinary ministers of holy Communion to assist in the purification of the sacred vessels.