He has unexpectedly drawn federal politicians from all parties together for a meeting of minds, in revulsion and disgust against his views.

The nation's leading atheist Julia Gillard is joined by the conservative Catholic Opposition Leader in opposing the cardinal as he clings to the notion that the law of the Vatican overrides the law of this land. Why should a priest who is told of sex abuse not be required to report this to police?

And many Australians would just see Pell as an embarrassment, noting his quick dismissal of the row over child sex abuse as a media ''beat-up''.

Nonetheless, the row over the confidentiality of the confessional is not the core issue. Nor should the Catholic Church be the sole focus of the inquiry, despite the Victorian inquiry being told that nine out of 10 cases of clergy sexual abuse involve Catholic priests or brothers. If the abuse occurred in a state-run juvenile detention centre, it must be investigated. And what about indigenous children in the Northern Territory still facing abuse?

Gillard has launched the most comprehensive inquiry into child sexual abuse in Australia's history. The royal commission will investigate churches, charities, state governments, schools, community organisations and the police.

The cabinet meeting late on Monday was a result of a crescendo of calls for action after fresh allegations last week about systemic abuses and cover-ups by the Catholic Church in NSW.

''Any instance of child abuse is a vile and evil thing,'' the Prime Minister said. ''There have been too many adults who have averted their eyes to this evil.''

How a single royal commissioner can get her or his head around the extent of the material on child sex abuse is hard to fathom. No matter how difficult that seems at this stage, it is a national imperative that this stain be addressed. It will take a very long time, given the Irish experience. And since the inquiry is potentially explosive, the findings will be harsh.

What differentiates this inquiry from other royal commissions is that it is not limited to a specific allegation. It will range broadly and will go where the evidence points, whether that is mistreatment of children in schools, community organisations, churches or child welfare agencies.

Gillard could have stonewalled on calling an inquiry but she didn't and the inquiry could prove to be a lasting legacy of her time in power.

The few days since the announcement have justified the PM's swift move - who could have predicted that Cardinal Pell's first response would be to blame the media? It will not be surprising if this refusal to face the facts is held up in later years as evidence for the continuing decline in the number of church-going Catholics.

Many, many children have been abused by Catholic clerics over the past 50 or 60 years. At least 500 clerics have faced allegations. It's on the record for all to see, except those who are blind to the facts.

After Pell's spray at the media for its ''smear'', he said: ''We'll answer for what we've done … we're not trying to defend the indefensible.'' The PM hopes to finalise the terms of reference for the royal commission at a meeting of premiers in early December. These guidelines must necessarily be broad but not so expansive that they set an impossibly big task.

Establishing the inquiry will be a test of how well federal, state and territory relations can work. Already there are hopeful signs, as Pell provides the impetus for a rudimentary show of unity across political parties.

A key goal of the inquiry must be an honest review of what has happened. This will involve great suffering and anguish by those who retell their stories, or reveal them for the first time.

The cries of the victims will echo for years, as they recount that no action was taken. We will be saddened to hear confirmation of numerous instances of a child being abused, and angry to hear repeated the fact that an abuser's colleagues turned a blind eye or simply sent the person to another locality, knowing that the cycle would reoccur. The PM is very conscious of the community outrage over this systemic cover-up and is insisting the inquiry will focus not just on those directly or indirectly responsible for abuse but also on those who enabled it by pretending it didn't exist.

When the Prime Minister heads overseas within days, this time to the East Asia Summit in Phnom Penh, the debate will continue here on the inquiry she has set in train.

Even though it will continue to have bipartisan support, she must also prepare for the following week, when Parliament's final sitting for the year could be a brutal affair.

While the four days of the session will be lightened by end-of-year parties, it is a crucial time for Tony Abbott to seize the agenda and impress on his team that he is not past his use-by date.

It's a big turnaround from Gillard's dark days.

Although Labor is still behind, the latest polls show the government's support continuing to climb, while voters appear to be increasingly turned off by Abbott's negativity. Adding to the Opposition Leader's problem is that Gillard is displaying the toughness her supporters say will get her through to the election.

With the carbon tax gone as a first-priority issue, the opposition will push a smear campaign against Gillard over her time as a lawyer, hoping to build traction during the election year.

Abbott may return to the topic next week in Parliament but he should expect the same steely defiance from the PM. His best chance for a line of attack is to claim the PM is ''running scared'' of making a formal statement to Parliament.

If he doesn't make an allegation about any impact on her current role, she will continue to bat away the questions, which look lame when compared with her lengthy press conference on the issue.

Without some new revelation, which has not been forthcoming over almost two decades, the issue can be run only as a grubby, background smear campaign. Meanwhile, the nation should be prepared to confront deeply disturbing revelations - based on facts - in the royal commission.

It is encouraging that the PM suggested the inquiry would take as long as it needed because it is only after the full exploration of the victims' claims that the healing can begin.

Ross Peake is Political Editor. Twitter: @rosspeakeCT