The cult of Mary, including Marian apparitions, has been very profitable–both literally and figuratively–for the church of Rome. For people who take a fancy to that sort of thing, it lends an emotional and popular appeal to Catholicism which would be lacking absent that phenomenon. Marian apparitions become tourist attractions and pilgrimage sites. They gin up lots of fervor.
I don't mean to suggest that this is purely cynical. I'm sure that many recent popes are genuinely devoted to the cult of Mary.
But although the papacy benefits from Marian apparitions, this is a potentially destabilizing principle. It's like dynamite under St. Peter's basilica. Just waiting to go off.
It's my impression that many pious Catholics are far more devoted to Mary than they are to the pope. After all, what's a pope compared to Mary? She's the Queen Mother of God. The Mediatrix and Co-Redemptrix.
And here's where it could get dicey. Take Lucia Santos:
Soon she had her first vision of an angel, a rather blurred apparition resembling, she told her family, "somebody wrapped up in a sheet"; the description drew much teasing from her siblings.
While watching over the family sheep with her cousins the following year, Lucia saw another angel, this time resembling "a boy of great beauty, about 14 years old, whiter than snow, transparent as crystal when the sun shines through it". Announcing that he was "the Angel of Peace", the apparition taught the children prayers, showing them a vision of a chalice above which he held the Eucharist, which was dripping blood. He revealed, in two subsequent visions, that Jesus and Mary had special plans in store for them.
Announcing that she was from heaven, the Virgin said that she would appear to them for six successive months, at the same place and on the same day each month, revealing her identity during the final vision.
Subsequently, she confided a terrible vision of hell "where poor sinners go", showing blackened souls floating in a fiery pool. If humanity did not repent, warned the Virgin, a second, more terrible war would break out.
This was the first of the Three Secrets of Fatima. The second predicted that Russia would return to Christianity and, in 1944, while gravely ill, Lucia sent a sealed envelope containing the contents of the Third Secret of Fatima to the Vatican, with strict instructions that it should not be opened before 1960.
By 1925, Lucia had entered their novitiate at Pontevedra, over the border in Spain, where she saw fresh visions of the Virgin and Child Jesus. In one, Mary told Lucia about a spiritual exercise she had mentioned at Fatima involving the faithful attending Mass on the first Saturday of each month for five consecutive months in order to offer prayers and sacrifice for the conversion of Russia. Later, the Child Jesus appeared to Lucia in the convent's backyard when she was taking out the rubbish, and urged her to spread this devotion throughout the world.
In 1929 the Virgin Mary instructed Lucia to tell the Pope about this and to ask him to say a special prayer, in union with every Catholic bishop in the world, consecrating the entire world - but especially Russia - to her immaculate heart. Only thus, said the Virgin, would Russia be prevented from spreading its errors (Communism).
When a letter from the Bishops' Conference of Portugal failed to elicit a papal response, Lucia's bishop and her spiritual confessor urged her to write a personal letter to Pope Pius XII. Despite strong misgivings, she complied, signing herself "the least of the daughters of the Church"; and, in 1942, the Pope made the consecration. However, he failed to ask the other Catholic bishops in the world to unite with him in prayer. In 1984, John Paul II repeated the consecration in Rome in union with the world's bishops. For years malcontents speculated that the consecration was incomplete; but in 1989, months after the fall of the Iron Curtain, Sister Lucia announced that "heaven" had accepted the Pope's 1984 consecration.
Notice that Lucia was supposedly Mary's mouthpiece. In regular communication with the Queen of Heaven! When Lucia spoke, popes listened!
No wonder! Lucia is taking dictation from the Mother of God–not to mention the Christchild. What pope can compete with that? Compared to that, he's pretty far down the pecking order.
Imagine having secret revelations from Mary which you can dangle, like a sword of Damocles. Technically, popes outrank nuns, but if the nun happens to be channeling directives from the Queen of Heaven, what gives?
Imagine if, in an interview, Lucia ever said Mary told her that John XXIII was an antipope or that Vatican II was a robber council? Who are Catholics going to side with–a pope or Mary's mouthpiece?
Now, Lucia didn't put Rome in that predicament, but given the proliferation of Marian apparitions, what happens if a future confidant of the Virgin Mary becomes a critic of the Vatican policy?
Catholics might point out that the approval process for Marian apparitions precludes that dilemma. If so, there are a couple of problems with that safeguard:
i) What if surviving visionaries of an approved apparition subsequently cite new encounters with the Blessed Virgin which take issue with developments in Catholic theology? Can Rome say, "On second thought, we take it back!"
ii) Moreover, if a Marian apparition achieves critical mass in popular sentiment, Rome can't afford to shut it down. Imagine the backlash if the Vatican were to say, "Based on historical renewed investigation, we've concluded that Mary's appearance to Juan Diego is a dubious legend. Please scratch Our Lady of Guadalupe from the list of approved apparitions."
To a great extent, the Magisterium becomes captive to the Marian piety which it fosters. It is simply ratifying popular sentiment. The popes–and Catholic apologists–had better keep their fingers crossed.