There are two ways of looking at what we know about the smearing of Maurice McCabe: a benign scenario and a malign scenario. The benign interpretation is appalling. The malign interpretation is chilling.

In one case, we are dealing with a cock-up of frightening proportions. In the other, we are dealing with a conspiracy that threatens the fundamental rights of every citizen of the State.

At best, we have a child protection system whose integrity has been undermined by astonishing incompetence.

At worst, we have a situation in which the two State agencies with the greatest power to destroy the lives and reputations of citizens have gone rogue.

Either way, it ought to be clear this is a scandal of immense gravity and import. It demands a response far beyond the setting-up of a commission of inquiry which has no powers to impose any sanctions on anybody. Nothing less than a full-scale criminal investigation is required. Our problem is that, since An Garda Síochána is at the very heart of this affair, this investigation can be credible only if it is led by officers from outside the State.

The benign scenario might be summed up in the title of the children’s horror fiction series A Series of Unfortunate Events. If it were fictional, however, it would be unpublishable. It relies on coincidences so extreme as to strain the credulity of the least-demanding reader.

This benign story yokes together two wildly disparate elements. The first is Maurice McCabe being a problem for the State. He is a good cop who becomes a pain in the neck because he can’t just keep his head down and ignore the laziness, incompetence and fecklessness of some of his colleagues.

Routine abuse

He sees the routine abuse of the PULSE system and of the penalty points system which is supposed to save lives by stopping carnage on the roads.

McCabe becomes a threat, not just because of his allegations but because his superiors at very high levels in the force look into them and decide there’s nothing there.

Instead of being a set of very serious but essentially local problems in Cavan, the dismissal of McCabe’s allegations now raises questions about the integrity and competence of some elements of senior Garda management. And that in turn is a political question – it spins outwards into the Department of Justice, the Minister for Justice and therefore the Government.

But as this first part of the benign story is escalating, a second, entirely unrelated narrative comes into play.

Who is Sgt Maurice McCabe? In 2008, Sgt Maurice McCabe raised concerns about quashing of penalty points. Claims that he was the subject of a smear campaign are to be examined in a tribunal of inquiry. The Garda whistleblowers: read more I found this helpful Yes No

A file is created in Tusla, the child protection agency, in 2013, recording an allegation that McCabe raped an eight-year-old girl. This would be a horrifying allegation in any circumstances, but here it is even more alarming because it is being made against a serving garda.

The creation of this file is followed by the Series of Unfortunate Events. Any one of these strange occurrences would merit an investigation – but there are four of them.

First, this allegation of a heinous crime against a serving garda sergeant results in no investigation: the complainant is not interviewed, McCabe is not interviewed. The file, so far as we know, just sits there in Tusla’s system, a black hole that exerts a gravitational pull.

It is no exaggeration to say this malign scenario has elements of a police state: an inconvenient dissident being destroyed by powerful arms of government abusing their powers.

Second, even though there is no investigation, the existence of the file and of the allegation it contains leaks out of an agency whose watchword is confidentiality. The idea that McCabe is a child rapist spreads through Garda, political and journalistic circles. It presumably helps to explain why the chairman of the public accounts committee of the Dáil, John McGuinness, claimed he was hearing “vile stories” about McCabe.

‘Administrative error’

Third, as McCabe gets more of a hearing and as the Guerin report begins to vindicate the substance of most of his allegations, the person in charge of his damning file in Tusla suddenly realises it is all a mistake. He or she writes to a superior, explaining the allegation on McCabe’s file did not relate to him at all – it was an “administrative error”.

He or she had somehow cut and pasted a report about another alleged child abuser from an unrelated file into McCabe’s file. This is a most unfortunate event. And, in an astonishing coincidence, it just happens to have occurred in relation to a person who was at the time posing a serious problem to Garda management, to the Department of Justice, to the minister for justice and to the Government.

But the Series of Unfortunate Events is not yet done with its catalogue of weirdness. There is yet another twist.

In January 2016, a full 18 months after Tusla had allegedly discovered its “administrative error” and realised McCabe had been horribly traduced, the same agency reactivated the now-discredited file and wrote to McCabe to say he would have to be interviewed to “decide if you pose a risk to children”.

Grotesque as this was, it led to McCabe’s discovery of what had been going on, not least to the devastating realisation that four of his children had been listed on the false file with the word “suspect” prefixed to their names.

This, remember, is the benign scenario. It is appalling on three levels. It has an extremely serious allegation against a serving garda going without even a cursory investigation. It has senior Garda figures spreading “vile stories” about an individual without having conducted any investigation into the veracity of those stories.

Bizarre procedure

And it has Tusla operating some bizarre procedure in which allegations can be cut and pasted between unrelated case files.

If McCabe was the victim of such a random set of coincidences, it means all adult citizens – and their adult children – could find themselves in the same situation.

The very possibility this could have happened is a threat to Irish democracy.

So even this benign scenario reveals casual scandal-mongering by professional investigators and a child protection agency that cannot protect its own most sensitive information.

And the malign scenario? Conspiracy theories should be avoided, but in this case the idea of a conspiracy is actually less outlandish than that of a cock-up. There is no evidence of a conspiracy – but, using ordinary standards of credibility, it is easier to believe in an element of design in this whole story than in a narrative requiring four extraordinary developments to succeed one another.

The unavoidable question is whether there was collusion to smear McCabe between some person or persons in the Garda and some person or persons at Tusla. All we can say at this stage is that a good criminal investigator would not rule it out without some plausible evidence to the contrary.

And if there is such collusion? We are in deep trouble. It is no exaggeration to say this malign scenario has elements of a police state: an inconvenient dissident being destroyed by powerful arms of government abusing their powers.

The very possibility this could have happened is a threat to Irish democracy. A State that has seen off subversion from without may be looking at something even more dangerous: subversion from within. It is not good enough to hope this did not happen – we have to know for sure whether it did or not.

And, with all due respect to the commission of inquiry that is to be established, certainty can only come from the outside.

Only a criminal investigation headed by senior officers from outside the State can produce either credible reassurances, if they are justified, or thorough punishment if they are not.