Last week saw the launch of a new political party in Ireland, something that would normally dominate the news here. We will come back to the fledgling party, which has the odd name of Renua, in a moment.

But the fact is that most of the headlines here over the past few days have not been about Renua. They have been about Sinn Fein, which is up to its neck in another sex abuse controversy.

It's a story that makes uncomfortable and depressing reading, but it cannot be avoided or ignored no matter how much Sinn Fein tries to minimize it.

It began last week when the BBC Northern Ireland investigative news program Spotlight presented the case of Louth man Paudie McGahon, who revealed that in the 1990s when he was a teenager he was raped by a senior Belfast IRA man. The rape took place when the IRA man was staying in McGahon's home, a so-called "safe house" on this side of the border.

McGahon's interview last week on the TV program was compelling viewing and utterly convincing. Following on from the Mairia Cahill and the earlier case of Liam Adams, brother of Sinn Fein president Gerry Adams, the cumulative effect is very damaging for Sinn Fein, giving a disturbing insight into how the party and its senior figures behaved in dealing with such cases.

Both Cahill and Paudie have shown extraordinary courage in making their cases public, as did Gerry Adams' niece Aine who was abused by her father Liam.

Those three cases alone would be enough to raise grave concerns about the Sinn Fein handling of abuse. But in the Dail (Irish Parliament) last week it was claimed by the government that this is just the tip of the iceberg and that there may be 100 such cases in the background. Cahill has suggested that there are at least 60 cases.

In the Dail last week reference was made to a leaked document which reveals that in 2006 a committee of four senior Sinn Fein figures secretly investigated at least 40 abuse cases involving members of the IRA and/or Sinn Fein.

As we know from recent experience in cases involving clerical sexual abuse, one person coming forward to tell their story usually leads to others finding the courage to also come forward, often after years of silence. The bravery of Cahill and McGahon in making their cases public is therefore likely to encourage many more victims of IRA abuse to come forward as well.

If there are 100 or more such cases out there, this is a nightmare scenario for Sinn Fein. What has started as a trickle of revelations could well turn into a flood.

As well as being shocked last week by McGahon's story (you can easily find the details on line) many people here were immediately struck by the similarity between how the Catholic Church and Sinn Fein have each dealt with the problem, giving priority to protecting their organization, failing to report cases to police, holding secret internal investigations, moving perpetrators away and encouraging victims to be silent. McGahon's case is a clear example of this, as was Cahill's.

Of course it is true that sex abuse is a problem that emerges in all walks of life, both here and in other countries. All political parties, just like all organizations, may have some members or former members who were involved in abuse.

But the problem in Sinn Fein/IRA appears to be on a different scale altogether, as it was in the Catholic Church. There is an obvious reason for this.

Sex abuse was a particular problem in organizations like the IRA and the Catholic Church because they were institutions that were powerful and feared, institutions that regarded themselves as separate from and above the law of the state. Given this power, members of the Republican movement and the Catholic Church were in a unique position to do what they wanted.

In the case of the Catholic Church, we know that in many cases offending clerics were not reported to the police, were dealt with under canon law rather that the law of the state, that secret inquiries were conducted by the church on that level, that perpetrators were moved to different parishes or different jurisdictions and that victims were told the matter was being dealt with and to remain silent. One such case led to the early "retirement" last year of the former head of the Catholic Church in Ireland, Archbishop Sean Brady.

In the case of the IRA and Sinn Fein, it is now becoming clear that something very similar has been going on. The IRA has, since the Treaty in 1921, always regarded itself as the legitimate government of Ireland and believes its legitimacy supersedes that of all subsequent Irish governments down through the years. On that basis it runs its own affairs and decides on what is lawful or not.

For that reason, when problems of discipline or criminal behavior arise within its own ranks, the Republican movement believes it has the right to deal with these matters itself, without reference to the state.

So in both Cahill's case and in McGahon's case, a Republican kangaroo court was set up to hear the evidence and pass sentence, a process that was highly intimidating to the victims.

We know that the perpetrator in Cahill's case ended up in Britain and the perpetrator in McGahon's case was moved to other places in the south of Ireland. It is now being reported that McGahon's abuser went on to rape a 12-year-old child in the south and two teenagers in Derry as he was moved around by the Republican movement.

The parallels with what the Catholic Church did, moving abusive priests around parishes with disastrous consequences for children, are obvious.

Another case now emerging is that of a 13-year-old girl who was abused by a person the media are referring to as a senior Sinn Fein figure in Dublin. And there are other cases which the media are predicting will become public in the coming weeks.

All of this puts the comments by Taoiseach (Prime Minister) Enda Kenny in the Dail some time ago when the Mairia Cahill case was making headlines in a new light. Kenny challenged Gerry Adams at the time to come clean about how many IRA abusers there were, how many had been moved to the south, and what information Sinn Fein had on their present locations. It now seems that Kenny and the security authorities here knew far more than we realized at the time.

The reaction of Sinn Fein to all this has been disturbing. Instead of really coming clean, as Kenny demanded, the party is trying to minimize the damage to itself.

The tactic is to accept the victims’ claims of abuse and offer sympathy, but at the same time to deny much if any knowledge of the kangaroo courts and what happened at them or since.

This is accompanied by calls to anyone with any evidence of abuse to go to the police and give statements, which is sickening given what we know about how Republicans behaved when first confronted with these cases.

Sinn Fein even attempted last week to take the high moral ground by calling for some kind of north-south body to be put in place to deal with all claims of abuse.

Even for Sinn Fein this shows a level of brass neck that is truly nauseating in the circumstances. It fools no one. Nor does the Sinn Fein claim that all this is all a manufactured campaign by the other political parties to damage them in the run up to the next election.

There is a very serious issue here of honesty and transparency which goes to the core of the wider question of whether Sinn Fein is a normal democratic party suitable to be part of a government. If it cannot be trusted on an issue of such sensitivity, how can it be trusted on anything?

There is no doubt that this scandal has the potential to seriously damage Sinn Fein. The latest opinion poll last weekend showed a slight slip in support for Sinn Fein and, as predicted in this column weeks ago, a further strengthening in popularity for the two government parties.

That trend, of a decline in support for Sinn Fein, the extreme left wing and the rest of the independents, matched by an increase in support for the government parties, is likely to continue in the months ahead. It raises the possibility that the re-election of the present government, or a variation of it, is now not as unimaginable as it was just a few months ago. The upcoming election is concentrating people's minds.

A very minor player in the next government might possibly be a few members of the new political party with the strange name launched last week.

Renua is clearly a play on the word renewal, and in Irish the words Re Nua literally mean New Era. So far it is light on detailed policy but very heavy on its commitment to be

entirely open, transparent and honest, promising to bring a new kind of politics here that is radically different to the wasteful, secretive, party-whip driven system we have now.

It is fronted by the former Fine Gael junior minister for Europe Lucinda Creighton who shines with enthusiasm and, possibly, naivety. It is clearly going to be a center right party, but there's not much more to be said about it until we see some policies. The cynics are already writing it off.

But it could well be a home for some disillusioned Fine Gael supporters who will never vote for Fianna Fail or Sinn Fein. Time will tell.

Paudie McGahon being interviewed last week.