The High Court will rule on Monday on an action taken by ten senators aimed at clarifying whether or not Seanad Éireann can sit and pass laws before the final 11 members are nominated by the next taoiseach.
President of the High Court, Ms Justice Mary Irvine, said the senators who took the case had asked for a judgment tomorrow but the the court "did not consider that was advisable".
She said the issues to be considered by the three-judge court were very serious and the most prudent course was to give a full written judgment on Monday at 9.30am.
The senators 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 ten plaintiffs are elected senators Ivana Bacik, Victor Boyhan, Gerard Craughwell, Annie Hoey, Sharon Keogan, Michael McDowell, Rebecca Moynihan, Rónán Mullen, Marie Sherlock and Mark Wall.
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 began yesterday and this morning lawyers for the State continued their arguments against the senators' action.
The State relies on constitutional texts which refer to a "vacuum of legislative power" arising from the inability to have a fully composed Seanad of 60 members if a new taoiseach has not been appointed.
In his closing argument for the State, Attorney General Seamus Woulfe SC said Article 24 requires a properly composed Seanad.
He said the taoiseach's exercise of discretion in relation to advising the president of a day to convene the Seanad was informed by the "principal consideration" that he, as outgoing taoiseach, could not nominate 11 members so he could not advise the president of the date.
The issue is whether that principal consideration is a valid one, the State maintained it was, and "all roads lead back to Article 18.8."
In closing arguments for the ten senators, senior counsel John Rogers said the State's arguments meant there is no parliament and Taoiseach Leo Varadkar is "immovable" until a new taoiseach is elected.
He said that was an unsupportable position and worse than legislative deadlock. "We are playing with fire and it is not permissible to take such risks."
Mr Rogers said the drafters of the Constitution could not have perceived there would be an interregnum in the legislative system in the way argued for by counsel for the State.
The drafters had envisaged circumstances where the legislative institutions can be convened to pass laws in the type of emergency governed by Article 24.
