There are seven men and women who sit as the Full Court of the High Court in Canberra.
Over the next three days, they will decide the futures of seven men and women who take their seats just up the hill in Parliament House.
From Tuesday to Thursday, the court will consider whether any or all of them breached Section 44 of the constitution, which disqualifies from Federal Parliament anyone holding an allegiance to a foreign country.
The wording is clear:
Any person who is under any acknowledgment of allegiance, obedience, or adherence to a foreign power, or is a subject or a citizen or entitled to the rights or privileges of a subject or a citizen of a foreign power, shall be incapable of being chosen or of sitting as a senator or a member of the House of Representatives.
The outcome matters enormously for the Turnbull government because one of the seven is Deputy Prime Minister Barnaby Joyce.
If he is struck out because of his now-renounced New Zealand citizenship, so too the Coalition government's one seat majority.
Mr Joyce enraged the opposition by refusing to step aside from cabinet during this saga, even though his Nationals ministerial colleague Matt Canavan did so after he discovered his Italian birthright.
Prime Minister Malcolm Turnbull told journalists on Monday he's "very confident" the High Court will rule in the government's favour, alleviating the prospect of a by-election in Mr Joyce’s NSW seat of New England.
"The government - based on the legal advice we have from the solicitor-general - is confident that the DPM and the other two senators, Nash and Canavan, will be found not to be disqualified from sitting in the parliament," Mr Turnbull told reporters in Sydney on Monday.
Essentially the government's written submission argues that because Barnaby Joyce (NZ), Matt Canavan (Italy), Nationals' deputy Fiona Nash (UK), former Greens Senator Larissa Waters (Canada), and independent Senator Nick Xenophon (UK) had no idea they were dual citizens, they should be excused.
But the Attorney-Generals' submission also states that One Nation Senator Malcolm Roberts and former Greens Senator Scott Ludlam, whose resignation in July set the dominos falling, should be ruled invalid.
Mr Ludlam moved to Australia as a child from New Zealand and never renounced his allegiance. He isn't contesting his case.
In the case of Senator Roberts, the High Court has already ruled he was British when he nominated as a candidate last year, although it is yet to be formally decided whether he took 'reasonable steps' to renounce the foreign citizenship. The court heard he sent some emails to non-existent email addresses as he tried to severe his ties to Britain.
And despite Senator Xenophon calling it quits last week for a return to South Australian politics, the outcome still matters as it will decide if the party bearing his name - NXT - replaces him as a casual vacancy or with a countback.
But that’s just the government’s point of view, the High Court could take a ‘black letter law’ reading of the constitution and rule them all invalid, clear some and not others, or clear them all.
This week the government will act as though it’s ‘business as usual’, but all concerned will be sweating on the outcome, which may be handed down after the hearings as early as Friday.