The Seventh Amendment added the bolded text to Article 18.4 :
1º. The elected members of Seanad Éireann shall be elected as follows:
i. Three shall be elected by the National University of Ireland.
ii. Three shall be elected by the University of Dublin.
iii. Forty-three shall be elected from panels of candidates constituted as hereinafter provided.
2º. Provision may be made by law for the election, on a franchise and in the manner to be provided by law, by one or more of the following institutions, namely:
i. the universities mentioned in subsection 1 of this section,
ii. any other institutions of higher education in the State, of so many members of Seanad Éireann as may be fixed by law in substitution for an equal number of the members to be elected pursuant to paragraphs i and ii of the said subsection 1.
A member or members of Seanad Éireann may be elected under this subsection by institutions grouped together or by a single institution.
3º. Nothing in this Article shall be invoked to prohibit the dissolution by law of a university mentioned in subsection 1 of this section.
How does "Provision may be made by law" oblige the Oireachtas to legislate in a particular way?
NB I am not opposed to this change but curious as to the legal challenge and possible implications. We were told during the repeal of the 8th campaign (which I also supported) that the constitutional change did not oblige the Oireachtas to legislate (although it was almost certain that it would).