Uncover the truth, but also lift lid on culture of secrecy
Was there a paedophile ring at Westminster? Was there a cover-up? The terms "cover-up and "Westminster paedophile ring" are volcanic. Put them together and there is bound to be an almighty eruption.
It is a statement of the obvious that these allegations are serious and needed to be treated as such. For sure, they will be. And the inquiry announced this week by Home Secretary Theresa May must address why there was no follow-up to the allegations when they were first made.
Before the latest inquiry gets under way, we already have two extremely important contributions. The interview on Monday's Today programme with the Conservative MP and former Northern Ireland Office minister Peter Bottomley was one of those rare, genuinely enlightening exchanges.
In the 1980s Bottomley was falsely accused of being part of a paedophile ring involving a children's home. The rumours were reported. Bottomley sued successfully. His experience is a reminder that some rumours are false.
False rumours are an important element in this bleak saga. They make it more difficult for those with a degree of responsibility to decide how to act.
The former Liberal leader David Steel has been attacked for not moving against Cyril Smith in the 1970s and 1980s (the rumours about Smith proved to be devastatingly accurate).
But for leaders with a thousand other more tangible responsibilities, acting on rumours that, in the darkness of the 1970s and 1980s, may have seemed improbable was there not a pressing priority. There was no way that a figure of Steel's obvious and demonstrable integrity would actively cover up Smith's monstrosities. In the context of the times there was no reason why he should have believed, or given much thought to, the rumours.
The second part of Bottomley's interview related to the current allegations of a cover-up involving an alleged Westminster paedophile ring. Bottomley was a minister in the mid-1980s and worked with senior officials at the Home Office. He expressed doubt as to whether these figures would have taken part in a cover-up.
Again, Bottomley makes a significant point rooted in the time when the allegations were made. It requires quite a leap to imagine the following thought process from senior Home Office officials: "We have evidence that some of our friends or colleagues are part of a paedophile ring. Let's kill the evidence in order to protect them and allow them to continue being paedophiles."
Perhaps we will find that such a sequence took place. But Lord Tebbit pointed us in a slightly different direction when he spoke of an "unconscious cover-up".
Tebbit suggests any suppression of abuse was unconscious. Yet the phrase evokes a sequence of events that is at least as plausible as an overt cover-up.
Perhaps some rumours were seen as without substance. Perhaps the source of some of the allegations, the MP Geoffrey Dickens, was not taken as seriously as he should have been.
The reaction of some commentators to the current Westminster sex abuse saga takes a more ominous direction. I read how disgraceful it is that nearly 200 detectives investigate the alleged wrongdoings of journalists and only seven are at work on the parliamentary paedophile investigation.
The fact that there might have been appalling abuses at Westminster does not mitigate newspaper misconduct, or the need for that misconduct to be fully investigated. And you can bet that now the focus moves to sex abuses at Westminster, the number of police investigating those allegations will increase.
As more light is shed on the dark decades of our recent past, a common theme emerges. It is not so much a conspiracy to cover up that gave public figures the space to abuse, but a lack of clear lines of responsibility within institutions.
At the BBC and in hospitals, managerial hierarchies were so convoluted that no one would think it their responsibility to reflect on and change the secretive culture. Without intense scrutiny, it was tempting to lead an easy life and not ask awkward questions.
We will know soon enough. From greedy bankers to abusive politicians and corrupt police officers, no one from the dark decades will escape the light.
But in each case we must learn the lessons and implement sweeping change for the future. The past has happened. Cries of cathartic shock are nowhere near enough.