Gerry Adams' interaction with his own flesh and blood, in the shape of his brother Liam and niece Aine, may prove to be the single most damaging element of his career. Yet it also reveals the struggles touching the man rarely seen behind the political mask.
Consider the conflicting loyalties facing the Sinn Fein leader when his niece confided in him back in 1987 that her father had been abusing her for years, since she was four.
He said he believed and supported her when she first turned to him about the sexual abuse. Yet he waited nine years to go to the police with information which backed up her claims.
Earlier this year, he told Belfast Crown Court that he loved his brother. Yet he gave key corroborative evidence for the prosecution which he knew could jail him.
Gerry Adams has lived with mental conflict about incest within his family for a long time. He has wrestled with it – the impact of those battles is visible on his face. He admits now that he'd take a different approach. And no wonder, because fault lines appear in his handling of Liam Adams' sexual abuse.
Gerry Adams' inconsistencies must have been influenced by two factors over and above the normal desire to keep a family's dirty secrets behind closed doors. Firstly, the authorities he should have contacted, in the interests of child protection, were the RUC – a force lacking the support of the nationalist population. Secondly, his enemies would have made political capital out of a dysfunctional Adams family.
It must have been a difficult decision for the Sinn Fein president to reveal that his late father had sexually abused family members, which he did in a perceptive interview by RTE's northern editor Tommie Gorman in December 2009.
Gerry Adams is 65 to Liam Adams' 58. It takes no leap of the imagination to presume he might feel he could have done more to protect his baby brother from their predatory father. Equally, did he do enough for his niece? She considers not.
Incest tears apart families, and from the various public comments he has made about this squalid business, Gerry Adams is scarred by it. As are others, not least Aine. But he is also a party leader and a public representative with broader responsibilities.
He appears to have believed that an admission in private from her father would satisfy Aine; the importance of a public conviction seems to have passed him by.
Where he is on really thin ice, however, is in his presumption that Liam Adams was no danger to others. He says he saw no evidence of Liam abusing children elsewhere. What a risk to take on their behalf. Substitute Cardinal Sean Brady for Gerry Adams. Now consider the circumstances again.
Gerry Adams had information substantiating an allegation of child sex abuse and sat on it for nine years. His brother confessed to him in 2000, but it was 2009 before Gerry Adams made a statement.
The problem for the Sinn Fein leader is not having a convicted paedophile in the family, but how he dealt with it. Sinn Fein has been critical of the Catholic hierarchy for its failure to grasp the clerical-abuse nettle. But Gerry Adams has relied on the same argument as bishops by claiming not to have understood abuse.
"When I heard that he was working in youth facilities again, I pressed him to leave and with one of the facilities I reported it to the authorities which were responsible for that facility," he said in the Tommie Gorman interview. "All I can tell you is that we now know much more about child abuse and how to deal with it than we did as I was developing my knowledge about it all."
Concealing sexual abuse is nothing new in Ireland, nor is the hope that it will all just vanish. But there is no doubt that he is wounded both personally and politically by this case. Taken in conjunction with persistent questions about Jean McConville and the Disappeared, the harm to his political career is likely to be significant.
Some sections of the public may sympathise with the dilemma he experienced. Family solidarity tends to be a given in Ireland, while rooting through family cupboards turns up any number of nasty surprises.
But when the political class scents blood, it moves in for the kill. Sinn Fein has drained support from Labour and Fianna Fail – Adams can expect no quarter from rivals. It will be used against him repeatedly.
The crux of the matter is that nine-year time lag before passing on crucial evidence to the police. Interviewed in 2007, he omitted his brother's 2000 confession. It would be another two years before he admitted it, shortly before a UTV 'Insight' programme was to be broadcast outing him for failing to report his brother's admission to the authorities.
THE two reviews in the Attorney General's Office and the Police Ombudsman's Office in the North will run their course. But what's rumbling away in the court of public opinion is a separate matter.
Gerry Adams has performed invaluable work for the peace process and nobody should seek to minimise that. I understand some of his actions, or lack of them – this is a complex story, after all. Yet it is also simple: children in west Belfast and Louth were left exposed by Liam Adams' access to them as a youth worker.
Oddly, Gerry Adams staked his faith on the police service and the courts delivering justice for his niece. But did he do enough personally to ensure it happened? Justice delayed is justice denied, after all.
His demeanour in recent times suggests he is grappling with this conundrum. Some Sinn Fein supporters may also struggle with it.