A specially convened division of the High Court has begun hearing an action by ten senators aimed at clarifying whether or not the Seanad can sit and pass legislation without the next taoiseach's 11 nominees.
They want a declaration from the court that there is no constitutional requirement for all 60 members of the Seanad to be appointed before it can sit and pass legislation.
The State argues the Seanad cannot meet and legislate until all 60 members, including the next Taoiseach's 11 nominees, are appointed.
The outcome of the case will be significant if a government is not formed this weekend as legislation for terrorist and gangland crime, including the operation of the Special Criminal Court, needs to be renewed by next Monday or it will lapse.
The case is being heard by three judges of the High Court, including the president of the court, Ms Justice Mary Irvine.
The group of ten senators who are taking the action include Labour senator Ivana Bacik and independent senator Michael McDowell, who is a senior counsel and former attorney general.
Senator Bacik is the only one of the ten senators attending the hearing due to social distancing measures in place in the Four Courts.
In his opening arguments to the court, Senior Counsel John Rogers, who is representing the plaintiffs, said there was a "legislative stalemate" in this country because of a political impasse but there is no constitutional lacuna.
Mr Rogers said this stalemate arises because of what he described as "an unjustified and improper interpretation of the Constitution".
He argued that it was not necessary for all 60 members of the Seanad to be appointed for it to sit and pass legislation. If this was the case, then article 18 of the Constitution would explicitly say that and it does not, he told the court.
Mr Rogers outlined the timeline of events leading up to the case. He said the current Dáil first sat on 20 February and went on to pass two pieces of emergency Covid-19 legislation in March. That legislation was passed by the previous Seanad.
The point about this was that the Seanad of an outgoing parliament enacted laws with the Dáil of an incoming Oireachtas so the Constitution has a facility for "an overlapping effect". This has happened on numerous occasions, he said.
Mr Rogers told the three-judge court that Seanad Éireann is at no point dissolved as an institution and remains in existence. Its members hold office until the day before polling day and, unlike the Dáil, it continues in existence.
However, he said since 3 April when new senators were elected "it all stopped" and for 74 days Seanad Éireann had not been convened.
Mr Rogers said that on 9 June the Dáil had approved the Loan Fund Amendment bill 2020. He said this was significant because it was the government engaging the legislative process of the Dáil, whereas in its defence to these proceedings, the State had said the legislative process could not be undertaken at all because of the current impasse.
He said the plaintiffs would contend that the Seanad election triggers certain constitutional events mandated by Article 18, including advising the President of the date for the new Seanad to sit.
He asked the court to imagine if the Covid-19 emergency had broken out on 4 April after the election of the new Seanad. "Our submission is that it was open to the Taoiseach to convene the Seanad then," he said, adding "it cannot be that it is postponed" indefinitely because you cannot nominate the Taoiseach's 11.
It is almost five months since the general election. The 33rd Dáil met for the first time on 20 February but has yet to nominate a member to be appointed as Taoiseach.
The new Taoiseach would normally then nominate 11 people to Seanad Éireann.
As this has not yet happened, Leo Varadkar has informed TDs, and senators, that the Oireachtas is not fully composed and cannot enact legislation. He says he is not in a position to advise the President to fix a date when the new Seanad can meet for the first time.
Lawyers for the State will argue that the new Seanad is not properly composed and not capable of meeting and carrying out its business until all 60 members have been either elected or nominated.
While the number of sitting members may vary by casual vacancy from time to time due to deaths and retirements, it must be constitutionally composed at the outset in accordance with Article 18.1, it will be argued.
The case is expected to last two days.