Mal Brough's mere presence as Special Minister of State is dragging down the Government. If the Prime Minister stands by him, he will have a lame duck - indeed, a next to useless minister - on his hands, writes Barrie Cassidy.

Why has Prime Minister Malcolm Turnbull not heard the deafening alarm bells around the Special Minister of State, Mal Brough?

It's troubling enough that he failed to see the risks in bringing Brough into the ministry even though the James Ashby/Peter Slipper affair was still to be resolved.

But not understanding that the situation for Brough had this week dangerously escalated brings his judgment further into doubt.

As Laura Tingle wrote in the Financial Review this week:

They [Brough and Wyatt Roy, Assistant Minister for Innovation] are being investigated by the coppers, for goodness sake. Brough's house has been raided.

And Brough is no ordinary minister. He is Special Minister of State, prompting the shadow attorney-general, Mark Dreyfus, to ask of the Prime Minister on Wednesday:

Is the Prime Minister's judgment so bad, or did he owe the member for Fisher so much, that he gave him responsibility for government integrity?

Then to exacerbate his problems, Brough gave clearly contradictory answers to precisely the same question: Did he ask James Ashby to procure copies of Peter Slipper's diary for him?

Last year, Brough told Liz Hayes on 60 Minutes that he did, and he went on to explain why he did it.

Sorry, this video has expired The honeymoon's over for Malcolm Turnbull

This week, he gave a flat answer - "No" - when the same question was asked in Parliament.

Staffers (like Peta Credlin) and ministers (like Mal Brough) should think seriously about their positions when their mere presence drags down the government. But they rarely do.

Prime ministers pay a high price when they, too, resist such obvious pressures.

The unfortunate fact for Malcolm Turnbull is that he has now been - albeit unwittingly - at the centre of two of the most sordid political exercises in the past six years.

The Godwin Grech episode in 2009 was the beginning of the end for him as Liberal leader the first time around.

Turnbull staked his reputation on the credibility of a Treasury official who forged an email in an attempt to ingratiate himself with the Coalition and try to bring down the Labor government.

When the facts were revealed, Turnbull's approval rating suffered the biggest single fall in Newspoll history.

Now, in standing by Brough, he immerses himself in yet another sorry saga where plainly Coalition figures - now ministers - went to extraordinary lengths to tear down the speaker, Peter Slipper.

Undoubtedly Slipper brought some of that on himself, but he was nevertheless subjected to the kind of persecution that hadn't been seen since Labor went after Senator Mal Colston in the late 1990s.

If Turnbull sticks by Brough then he will have a lame duck - indeed, a next to useless minister - on his hands.

Useless in this sense: Brough will not be able to hold a news conference - a basic requirement of any minister - without having to tackle questions like those Mark Dreyfus asked of him on Monday.

As examples:

Does the minister ask the Australian Federal Police to investigate when staff members employed under the Members of Parliament (staff) Act provide unauthorised access to a member of parliament's official diary?

On 29 March 2012 the minister texted his email address to James Ashby so that he could be sent a better quality copy of the speaker's diary. Ashby replied, and I quote: 'Done. Coming through in a minute.' Did the Minister receive those unauthorised copies of the speaker's diary? Is conduct of this nature consistent with the standards the Government applies to this Minister's portfolio?

On 29 March 2012, now former journalist Steve Lewis sent an email to the minister which read: 'On how many occasions has Peter Slipper travelled to New Zealand since July 2010?' Did the minister agree to obtain unauthorised copies of the speaker's official diary for a journalist?

And on and on it went.

And so will the controversy - until such time as Brough is able to openly and completely answer questions like those.

***

One final note on a story that hasn't yet drawn widespread national attention, but should.

Australian Border Force has suspended a program by a group of nuns in Melbourne who routinely take children from the Broadmeadows detention centre on outings to places like the Melbourne Zoo, the Collingwood Children's Farm and various parks for picnics.

They have done this because, they say, the nuns do not provide adequate supervision and some of the places they visit are inappropriate.

They would have been better off saying nothing and putting it down to "on playground matters".

Tony Abbott was right about one thing when he said that nothing changes when you change leaders.

No matter who is running the country, the Government is still capable of being cruel to the children of asylum seekers. On that issue, we remain an international embarrassment.

Barrie Cassidy is the presenter of the ABC program Insiders. He writes a weekly column for The Drum.