Some cast ICAC as the ogre that's brought down a good leader - and a woman at that - over what seem to them relatively small matters.

Others argue propriety is paramount, regardless of the broader qualities of a leader, and Berejiklian's position as NSW premier became untenable after her revelation last year of a relationship with a dodgy colleague.

Deputy Prime Minister Barnaby Joyce portrayed ICAC as a rogue player that gets in the way of politicians.

"ICAC out of control means that the bureaucracy reigns supreme and politicians are basically terrified to do their job," Joyce told Channel 7.

"Politicians at times have to make hard decisions. It's not that they're corrupt, they're making decisions. There might be some disagreement with the bureaucracy, but that's their right. That's why people go to a ballot box and they see the name of politicians on the ballot paper, not the names of bureaucrats."

Joyce's line ignores a couple of salient points.

Politicians' decisions in some cases are made for improper reasons. And without sharp oversight, the voters may not be the wiser when they look at that ballot paper.

With the Morrison government due within weeks to introduce its legislation for a federal integrity commission, Berejiklian's resignation has brought into even sharper focus the powers and conduct of bodies charged with investigating integrity in politics.

Morrison was blunt about ICAC. "I'm sure there are millions of people who've seen what's happened to Gladys Berejiklian, they'll understand that's a pretty good call not to follow that [ICAC] model," he said.

Many people, however, won't think that's such a "good call".

We haven't got the final version of the government's integrity commission legislation. But the draft model put out by then-attorney-general Christian Porter was spineless in its provisions relating to politicians and public servants. And it would take a major change of direction for the government to insert a significant spine when it makes its revisions.

The point is this: the government doesn't really want an integrity commission. It has been dragged to it by political necessity.

In the draft model, the proposed commission has tough provisions covering the scrutiny of law enforcement bodies. But politicians, their staff and bureaucrats would be given heavy protections.

These would make it hard for allegations to reach investigators, limit what matters the body could probe, and ban public hearings during inquiries, as well as public reporting.

Under Morrison's model, Berejiklian's self-damning 2020 evidence would not have been given in an open forum.

In a report released this week, the Centre for Public Integrity, an independent think tank with a board of legal heavyweights, compared the government's planned commission with others around the country and concluded that its public sector division "would be the weakest integrity commission in the country".

The centre pointed out such a body wouldn't be able to investigate rorting in the sports grants scheme and commuter car parks project, allegations of conflict of interest involving minister Angus Taylor's family business, or claims about ex-ministers' potential breaches of the ministerial code of conduct.

This list, however, does invite a knotty question. Should all alleged integrity breaches by politicians, staff and public servants be examined by the same body?

Gary Sturgess, who as cabinet secretary to the NSW Greiner government designed ICAC, argues for having one body to look at serious "corruption" allegations (with no special protections for the political class), and a separate one to deal with less serious alleged integrity breaches by public figures.

Sturgess warns against confusing corruption involving potential criminality with other (but still important) breaches. "Treat all politicians as crooks, and there is the danger that we will end up with less integrity in public office, not more," he wrote in The Conversation this week.

In designing its model, the Morrison government has been more concerned about the political damage a robust body could do than about corruption and other integrity issues. It doesn't want any more opportunity than presently exists for "scandals" to be probed.

Critics of having a federal body at all have in the past argued that "corruption" is found more often at state rather than federal level.

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But there's no doubt federal governments of both complexions, and individual politicians, will often be willing to subvert proper process when it's expedient to do so - and if they think they can get away with it. And the role of donations in buying access to ministers and their offices involves serious integrity concerns.

Potential exposure of integrity breaches has the dual advantage of serving the public's right to know and acting as a deterrent to bad behaviour.

But the fear that an integrity commission can be weaponised politically is legitimate. Strong protections are needed for those investigated - and witnesses - as well as stringent arrangements for oversight of the commission's activities.

Labor is promising a more robust model to cover the political class, including public hearings, wider access for those wanting to make allegations, and the ability for the commission to commence its own inquiries.

Retrospectivity is a contested area, with shadow attorney-general Mark Dreyfus saying the commission "has to be able to decide about matters that potentially, even though they occurred in the past, are having a current effect on the government of Australia". The government says retrospectivity is a question of parameters and it is still working this through.

The government's legislation may not be passed by the election, given the tight timetable. Even if it is, Labor will be committed to revisiting the model.

Either way, the national integrity commission is likely to be still a sharp point of contention when voters go to the polls.