When Sir Owen Glenn announced that he would fund an inquiry into domestic violence and child abuse, he should have laid everything on the table. That would have removed the prospect of unpleasant surprises that could disenchant inquiry members and, ultimately, derail the worth of the whole exercise.
But that has occurred with the revelation that Sir Owen was accused of physically abusing a young woman in Hawaii in 2002. Never mind that this happened more than a decade ago, or that the millionaire philanthropist offered a "no contest" plea, or that the charge was dismissed when a six-month probationary period ended. The Glenn Inquiry is now damaged severely. There seems little even Sir Owen could do now that could start to repair this.
The latest disclosure comes on top of the resignation of most of the inquiry's senior members. Chief among these was its founding director, domestic violence campaigner Ruth Herbert. She and three of the inquiry's four co-chairs quit, citing safety concerns for survivors of family violence giving evidence to the inquiry.
But that appeared to be only one of several sources of disaffection. If there was any doubt about the effect of the Hawaiian abuse allegation on top of this upheaval, it was answered by the reaction of Ms Herbert and the inquiry's former operations director, Jessica Trask. "We are lost for words," they said. "Our immediate reaction is that it is the ultimate betrayal of the trust we put in him."
Sir Owen's problem is not only one of omission. Over the past 12 months, he has signed two declarations stating he has no history of violence towards women or children - one for the inquiry and one for the White Ribbon anti-violence campaign, for which he had applied to become an ambassador. That involvement was this week abandoned. The anger of Sir Owen's critics is hardly likely to be lessened by the fact that he says he stands by these declarations, and is happy to defend his decision not to tell either organisation of the Hawaiian charge.
The Honolulu court records cited by Fairfax Media show Sir Owen was accused of intentional, knowing or reckless physical abuse of a woman. He says there is no truth to the allegation, and he regrets not taking the matter to court. On the strong advice of an American lawyer, he had decided after two years of dispute to resolve the case to avoid further "horrendous" court costs. That may well be so, but the manner in which the accusation was dealt with - the peculiar American stance of neither admitting nor denying the charge - has ended up increasing the harm to his inquiry.
That must now be addressed. The significance of the damage cannot be ignored. New chairman Bill Wilson, QC, may be right when he says, "the importance of the inquiry is paramount and is where we would rather be channelling our energies". But all that energy will count for nothing if the inquiry has lost much of its credibility.
Sir Owen could belatedly reclaim some accountability if he was to disclose the detail of what was alleged to have happened at the Aston Waikiki Beach Hotel on that night in September 2002 and why the allegations did not bear scrutiny.
If he chooses not to do this people will be left with the bald facts of an accusation of abuse, not contested before a court and later dismissed. Sir Owen can press on with the inquiry; that is his right, as he is financing it. But he must surely recognise that the series of resignations delivered one significant blow, and that an episode in his past which continues to be unexplained might well deprive the inquiry of any hope of gaining public confidence.