The Petition of Concern has been in the news at various times over the past decade. Since 2007, only the DUP had the power to trigger one on their own, whilst Sinn Fein always needed another party to one above the required 30 MLAs.
The Irish News reporter, Brendan Hughes has a nice little graphic explaining the various parties positions on this issue
The issue came to the fore this week in a meeting between the DUP and the group Love Equality as the BBC Political Editor, Mark Devenport reports;
The Love Equality campaigners expressed disappointment that the DUP will not guarantee it will not try to use a petition of concern if a same sex marriage bill comes before the assembly in the future.
The DUP can no longer trigger a petition by themselves and one this issue they would need another two MLAs to come on board.
Devenport does highlight a proposal from the Alliance Party;
Alliance has shared a proposed protocol with other parties which would limit the use of petitions of concern to matters of national identity; matters which relate to the legacy of the conflict in Northern Ireland; or matters which relate to the constitutional structure and institutions established under the Good Friday Agreement.
Alliance suggests a five-strong panel of legally qualified people could be appointed to adjudicate on whether future petitions meet this criteria.
David McCann holds a PhD in North-South relations from University of Ulster. You can follow him on twitter @dmcbfs