On Tuesday, the High Court will begin hearing the cases of the ???Citizenship Seven', as Enid Blyton might have dubbed them.
These are MPs of the Australian Parliament who were dual citizens.
They are all Australian citizens who, unknowingly, had become or remained nationals of another country through the gift of foreign law.
Under section 44 of the Constitution, this may make them ineligible to not only serve but have been elected in 2016. Here, I'll explain broadly what the Court must decide, and the consequences.
Who are the seven?
Deputy PM Barnaby Joyce (Nationals, NZ); Deputy Nationals leader Senator Fiona Nash (Nationals, UK); former minister Senator Matt Canavan (Nationals identifying LNP, Italy); Senator Nick Xenophon (NXT, UK); Senator Malcolm Roberts (One Nation, UK); Ex-senator Larissa Waters (Greens, Canada); Ex-senator Scott Ludlam (Greens, NZ).
What must the court decide?
Under current law, MPs are okay if they took ???reasonable steps' to renounce prior to nominating. Only Malcolm Roberts took any steps, but his effective steps were belated.
The government and non-Greens MPs also argue it was unreasonable to expect steps to be taken, unless the MP was born overseas to non-Australian parents.
They argue the only real purpose of the law - to avoid possible conflict of allegiance - can't be breached by MPs who weren't on notice they might be dual citizens.
What is the Greens' position?
The Greens senators resigned after learning of their dual citizenships.
They didn't have to: only a court can declare an MP ???unelected'.
The Greens are sticking to their guns. They want a ruling that all the MPs were in the same boat.
Aren't they all guilty as sin?
Negligent, perhaps. But none knowingly breached the Constitution. In some cases, the dual citizenship arose through the vagaries of evolving foreign law in relation to their parents.
Once aware of it, all immediately renounced their overseas citizenship (except Ludlam who seems not to wish to continue his political career).
So far, no Labor or Liberal MPs have been caught in the net. It pays to afford good legal advice.
Which way will the court go?
Unlike the marriage survey case, the bookies aren't offering odds.
I'd guess it is 60:40 likely that the Court will take a firm, literal reading of the Constitution and cut off heads "to encourage the others" to take more care in future.
When will we know?
Who knows? There are up to three days of hearings. After that, the court will try to expedite its ruling.
But this is a complex set of cases, jammed into a busy schedule already upset by the urgent case on the legality of the marriage survey.
In that case, the Court ruled quickly, then spent 3 weeks crafting formal reasons.
What happens then?
Any disqualified senator will be replaced by the next candidate on their party's ticket at the last election. This fits the party voting system for Senate elections.
So Andrew Bartlett may return as Greens senator for Queensland, until the next election.
But a party can lean on the recipient of such a windfall gain, and ask them to resign. If so, the State Parliament fills the vacancy on the nomination of the party. That has been mooted as a backdoor re-entry method for Senator Roberts.
Weirdly, if the government's argument wins the day, Waters will not be disqualified but she has already resigned.
The Greens would be in an exquisite dilemma: nominate her or Bartlett?
And to add mischief, if Premier Palaszczuk dissolves the Queensland parliament for an early election, the Greens may suffer a prolonged agony.
In the House, disqualified MPs face a fresh election.
In Joyce's case, he will surely win. Being an accidental Kiwi hardly makes him a fifth-columnist. But pity the poor electors of New England, flooded by every news outlet and carpetbagger in the land.
Did it have to come to this?
Parliament did not have to refer these cases to the High Court. Had it realized it faced a systemic issue with credentials, it could have had an audit and amnesty.
Parliament has an ancient power to rule on any MP's qualifications.
Since Parliament referred the cases and no MP was fraudulent, the taxpayer foots the legal bills.
The system pays too, as the saga has increased voter cynicism.
And next year's election will be marred by media and rivals looking for gotcha moments in the ancestries of candidates.
Tell Me More!
Come to a free public lecture on the topic. At UQ, St Lucia campus, Monday, October 16, 6pm. I'll give a deeper critique of the section 44 mess. See here for details.
Graeme Orr is a professor of law at UQ and author of books such as The Law of Politics.