While it would have been much easier for the Government if Barnaby Joyce had stood aside from Cabinet while the High Court determined his parliamentary eligibility, the Nationals leader was too big a fish for that to happen.

But the political price of his retention is substantial, as Monday made clear.

Labor started the parliamentary week with a suite of questions about the citizenship imbroglio, including interrogating Malcolm Turnbull about the possible illegality of the ministerial decisions Mr Joyce and his deputy, senator Fiona Nash, are now making if the court doesn't go as the Prime Minister so confidently predicts.

Let's be clear. This wasn't Labor rendering the Parliament chaotic, as some earlier hype had anticipated. Rather, it was a proper use of Question Time to pursue detail the Government would rather avoid, and highlight a potential problem.

Mr Turnbull argued Labor was playing politics "at a time when we face the gravest threat to peace on the Korean Peninsula, at a time at home when we have Australian families and businesses bearing the brunt of higher and higher electricity prices".

Well, that's true, but the matters being raised are legitimate.

For instance, constitutional experts warn that if the High Court ruled against the ministers, the decisions they made in this period could be legally problematic.

A person can be a minister without being a parliamentarian for three months under the constitution.

But if the High Court declared Mr Joyce and Senator Nash ineligible and the three months dated from the election, the grace period would not protect these decisions.

Shorten keeping the heat on Joyce

For the Government, the worst of the situation is that the pressure on Mr Joyce is a well to which Labor can keep returning, especially at the moment.

When Mr Turnbull goes to the Pacific Islands Forum late this week, Mr Joyce briefly becomes acting prime minister.

Sorry, this video has expired Abbott tells Shorten to provide proof of renouncing citizenship

To keep the heat on Mr Joyce, Bill Shorten decided to accept the Government's challenge and finally produce the evidence that he properly renounced his British citizenship before entering Parliament.

Like Mr Joyce and Senator Nash he had dual citizenship by descent — but, unlike them, he was aware of it and dealt with it.

Mr Shorten had repeatedly resisted producing the documentation.

It had been thought that, while he was certainly OK, he didn't want to expose any of his colleagues whose affairs mightn't be in order, despite the ALP's rigorous checking process.

On Monday morning Tony Abbott flourished evidence of renouncing his own British citizenship and said Mr Shorten should do the same.

"Show your letter or shut up about Barnaby Joyce," Mr Abbott said. Mr Turnbull pressed the point in Question Time.

Mr Abbott would have been pretty happy that his action was followed so soon by a result.

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Citizenship issue not going away

By tabling his documentation, Mr Shorten in theory may have made it harder for others to resist demands for paperwork.

But one suspects the Government has lost the will for this chase.

Recently the position of Labor's ACT senator Katy Gallagher, whose mother was born in Ecuador of British citizens who were in that country temporarily, has come under some question.

In a statement to the Senate on Monday, Senator Gallagher quoted two legal opinions supporting her eligibility. That looks to be that.

Most immediately, Mr Shorten has stopped the Government being able to divert attention from the Joyce situation onto the furphy about him.

Having erected the barricades around Mr Joyce and Senator Nash, the Government will face continuing attacks — until things get better when the ministers receive the all clear, or very much worse if the decisions are adverse.

The Government's only counter is its argument that Labor is concentrating on political point-scoring when the nation's sights should be higher, and the ALP does have to take some care on that front.

As the citizenship issue continued to gnaw at the Government, the Coalition trailed in the 19th consecutive Newspoll.

Labor's two-party lead has narrowed from 54-46 per cent to 53-47 per cent in a fortnight, and the Coalition's primary vote was up two points to 37 per cent, but in voting terms this was another status quo poll.

From the Government's perspective, the encouraging change has been Mr Turnbull widening his lead as better prime minister from 10 points to 17 points.

Last week Mr Turnbull was going out of his way to show he was focusing on power prices, so preoccupying for many voters.

There was the helicopter ride to the Snowy and the summoning of electricity chiefs to Canberra again to tell them to give consumers better information about the best deals to lower their bills.

But these are easy gestures, as the battle within the Government looms over a clean energy target — the seminal policy decision between now and the end of the year.

Michelle Grattan is Professorial Fellow at the University of Canberra.

Originally published in The Conversation