Bishops don't resign.
Like all members of the Roman Catholic clergy they have pledged themselves to obeying those above them in the hierarchy. Therefore, if they want to remain in good standing with Church authorities they seek permission from the Vatican to go.
And sometimes they get it. And sometimes they get the assurance that their departure is neither appropriate nor desirable.
There have been huge embarrassments for the Church around the disclosure that bishops and cardinals have failed to report abuse to the police.
The outstanding case was that of the former primate, Cardinal Sean Brady, who had debriefed two boys abused by Brendan Smyth, a priest in the Norbertine Order.
Cardinal Brady had sworn the boys to secrecy and had seen it as the fulfilment of his duty to report his findings to his bishop, even as the odious Smyth continued to abuse.
So Bishop John McAreavey's decision to resign in the face of intense heat from the media is unusual both because it was prompt and because it appears not to have involved consultation with the Vatican.
In the past shamed bishops might be summoned to Rome and papal deliberation would take weeks.
That's not how it works now and it appears not to be how the Vatican wants it to work.
Two years ago Pope Francis approved measures for sacking bishops who were implicated in the familiar cover-ups by which paedophile priests were shunted around to preserve the Church against scandal.
So it is possible that Bishop McAreavey knew that the Pope would not indulge him.
He had known since the 1990s that Malachy Finnegan, the former president of St Colman's school in Newry, had been raping boys yet he had colluded in the charade by which the creep was presented to the community as a decent man of God.
He had shared the altar with him at a Mass and had even officiated at his funeral.
Bishop McAreavey's position was made untenable not just by media pressure but by the frank concern of parishioners, some of them going as far as to refuse to allow him to confirm their children.
And now a scandal, whose impact the Church was recovering from, is back at the heart of public debate and Ireland is reminded that the Church harboured the most odious and dangerous of sexual predators, those who go after children.
People are now much more aware of the damage done by those priests following the courageous disclosures of several victims. They now know that the pain inflicted on a raped child may damage the mind almost beyond repair.
The question is: what happens next?
More than a decade ago we got the huge disclosures of reports into the scale of abuse and cover-up in two Irish dioceses, Dublin and Ferns.
The shock produced by these reports seemed as much as Catholic Ireland could bear and the full horror did force the Vatican to concede change, at first grudgingly and cosmetically.
Rome summoned the people to prayer as if the answer lay in the purification of the souls of the laity. We got a papal letter and a eucharistic conference and a commitment to more efficient dealings with complaints.
But a grisly fact remains - we did not get full disclosure.
Two dioceses opened their files to investigation, Dublin and Ferns.
There are 23 others that didn't.
Unless those 23 are all uncharacteristically pure, then more paedophiles are listed in their records and other bishops know who they are or were.
Surely those files should all be opened now.