Since the early 1980’s a new question has arisen and been answered.
Canon 2370 of the 1917 Code of Canon Law provides: “A bishop who consecrate another bishop, the assistant bishops, or the priests 1 who in place of the bishops assist the consecrator, and the newly consecrated bishop who receives consecration without an Apostolic mandate in violation of the precept of Canon 953, are all automatically suspended until the Apostolic See shall have relieved them of the penalty.” On April 9, 1951, Pope Pius XII added an excommunication most specially reserved to the Holy See for consecrating a bishop not nominated or expressly confirmed by the Holy See.
Father Anthony Cekada wrote an article on this in which he says: “No traditional Catholic bishop – at least none of our acquaintance – has been consecrated to the episcopacy and then received illegal designation and title to a diocese established by the Roman Pontiff.” 2 He then claims that the excommunication promulgated by Pope Pius XII for consecrating bishops does not apply to Traditionalist bishops, because they are not consecrated and given the Office of Bishop.
Let us consider Father Cekada’s theory. The reason for the excommunication was because the Chinese government was appointing men to vacant diocese in China to be consecrated as Bishops of these dioceses. Father Cekada has established at least a probable opinion that the consecration of bishops by the Traditionalists does not incur the excommunication Pope Pius XII instituted. Under Canon 19, excommunication must be interpreted strictly, therefore the Traditionalist bishops do not incur the excommunication.
Let us look at the reason given. Traditionalist bishops are not consecrated to the Office of Bishop of a diocese, therefore they have no jurisdiction as a Bishop of a diocese, but must claim their authority from some other source.
1 If three bishops are not available, the consecrating bishop should be assisted by priest co-consecrators to fill the number three up. However, those outside the Catholic Church usually do not provide priest co-consecrators. And so by their manner of acting we can conclude that the Traditionalists are outside of the Church, for in the consecrations by Bishop Ngo-Dihn in 1981, no co-consecrators were employed. The same is true of the consecration of Father Musey by the two Mexican bishops in 1982. Archbishop Lefebvre did not employ a priest co-consecrator to assist him and Bishop de Castro Meyer in 1988, when they consecrated four bishops.
2 http://www.traditionalmass.org/articles/article.php?id=59&catname=10