In two cases of sexual abuse we know that Gerry Adams' behaviour was simply wrong

Gerry Adams has now twice shown himself to have questions to answer regarding his dealings with sexual abuse allegations. He has a track record of prioritising the organisation above victims - he did it in the case of his own niece, raped by her father. The Sinn Fein leader delayed Aine Adams' search for justice because it was in his interests to hush it up. Finally, she went to the police in 2006 because it was clear her uncle was going to do nothing about his paedophile brother. "I realised it was all about PR and protecting his own image," she said.

In backing their president to the hilt, Sinn Fein politicians are exposed if further victims emerge. But they are already undermined: how can they talk about protecting the vulnerable from welfare cuts when the vulnerable weren't protected in sexual violence cases? Sinn Fein's female representatives are particularly damaged: one after another, they have failed Ms Cahill.

And what of Gerry Adams, from whom they take their lead? Secrets and procrastination were his approach in Aine Adams' case, and equivocation in Mairia Cahill's. His actions are far from acceptable and his version of events is far from credible.

Let's put it in context. It was in the IRA's interests to shut down victims pointing the finger at anyone in the republican family. Sex crime allegations were used as leverage by the security forces in the North, with attempts made to turn either the accuser or the sex attacker into an informer. Aine Adams first went to the police in the 1980s, but backed off because they tried to use her to gather intelligence on her uncle. That's partly why the emphasis was on protecting the organisation rather than the victim. But chances were taken with children's safety.

Gerry Adams waited nine years, by his own account, before passing on evidence that his brother had admitted sexual violence against Aine. He told a Belfast court that his brother confessed the abuse to him in 2000, but didn't go to the police until 2009. Finally, he did so a month before he was due to be interviewed for UTV's 'Insight', in which Aine went public. That was intended to forestall criticism that he had withheld evidence about child sexual abuse.

Last year, Liam Adams was convicted of raping and abusing his daughter over a six-year period, beginning in 1977 when she was only four. Gerry Adams tried to block reporting of the case by asking Aine to seek a court injunction. This was presented as shielding her rather than an attempt to block scrutiny of his behaviour. He said he was told Liam had only abused "the once" and did not believe he was a danger. What competence did he have to form such a judgment on his brother's risk of re-offending? Arguably, he evaded the level of scrutiny his actions deserved because he sheltered behind Aine's natural distress: calling for privacy for the family.

So, are we really to believe that a man who hindered his own niece's search for justice was supportive of Mairia Cahill? He failed his niece, and acted with a similar callousness towards Mairia Cahill. If there are more victims, it will take an exceptionally courageous one to come forward now.

Let's revisit his behaviour in the Aine Adams case. He admits he had no doubt from 2000 onwards that his brother had sexually assaulted her, but saw no conflict between that and Liam working with teenagers in a variety of youth clubs. Liam Adams worked with children on an estate in Dundalk from at least 1997 to 1998; for the Clonard Youth Project in West Belfast in 1998-2003; he did youth work in Dundalk at Cox's Demesne Community Centre; and worked at Beechmount Community Centre from 2004-2006. Adams had to be aware of his brother's access to teenagers.

However, he did not alert social services to the allegations. He said he told Liam's second wife Bronagh, mother to at least two more daughters, and conceded that she did not believe him. Therefore, what assurance did he have that those nieces would be protected? He also said he told the authorities in Clonard and named a Father McGoran as recipient of this warning. The priest is now dead and cannot verify it.

At Liam Adams' first trial in Belfast, Gerry Adams said he told his brother he shouldn't be working with young people. Barrister Eilis McDermot pointed out that simply having a word with Liam was inadequate - he had the power to ensure someone suspected of being a child abuser was denied access.

"I didn't bring it to Liam's attention in a, you know, dictate sort of way. I tried to reason with him," Gerry Adams said in the witness box. Ms McDermott asked if he had brought it to the police's notice. His reply washed his hands of any responsibility. "I didn't, because at this point Aine was an adult," he said. "This, insofar as we know, was a legacy issue. I am not Aine's parent. I am an uncle and she has many uncles. And I was trying my best to resolve these matters in a way which helped Aine, but also, if I may say so, in a way which allowed Liam to get rid of these demons." Liam's demons?

Gerry Adams had a clear duty to stop his brother taking those jobs. Sinn Fein could have found him other positions. His inability to accept that shows he did not understand the nature of abuse. Yet he claimed to be able to know when someone was at risk of re-offending. "I didn't believe at that point (1998) that my brother was a danger," he said. Without any training, he regarded himself as fit to decide that his brother was safe around children. That was a huge chance for Gerry Adams to take.

His dishonesty emerged in another way during that court case. Gerry Adams had already said he had nothing to do with Liam Adams for 15 years, from 1987 to 2002. But a sequence of photographs presented in evidence told a different story. Among them were photographs of him with Liam at his brother's second wedding in 1996; attending the christening of Liam's second daughter in 1997; canvassing with Liam in 1997; and at a 2003 presentation in Clonard Youth Club.

In his 1996 autobiography 'Before The Dawn' Gerry Adams made 11 references to his brother without any suggestion of estrangement or wrongdoing. "I want also to thank Colette, our Paddy, my father, brothers and sisters, especially Liam" said the dedication. Adams has nine siblings. But Liam was the one he mentioned.

Far from being ostracised by Sinn Fein, Liam Adams remained active within the party. At one stage, he sought the nomination as Sinn Fein's candidate in Louth in a Dail election, but withdrew his name after it became clear another republican contender had more support. It is inconceivable that his name went forward without his brother's knowledge.

So, from first to last in relation to her rape and abuse, Gerry Adams's behaviour towards his niece Aine was just plain wrong - and the same can be said for his dealings in the Cahill case. He allowed organisational loyalty to trump both child protection and victims' rights. Mairia Cahill was interviewed for six months until March 2000 by the IRA over her rape allegations, a time frame which suggests a process designed to encourage her to retract.

Sinn Fein's inability to deal with the ethical questions raised by these cases compromises the party's credibility. Its response has been to deflect - to muddy the waters by claiming media bias. But I have a question for the party: why does this message send you into such a tailspin that you prefer to shoot the messenger rather than confront the issues?