New York Times,
"January, when Northern Ireland’s governing coalition collapsed. That created a power vacuum at Stormont that has still not been filled, paralyzing the region’s already pinched institutions and threatening a 1998 peace deal that largely ended three decades of fighting between nationalist and unionist factions.
Since that deal, known as the Good Friday Agreement, Northern Ireland has been run mostly by a devolved regional government that must, in effect, be led by a coalition between the region’s largest nationalist party and its largest unionist counterpart.
But in January this delicate arrangement was upended when Sinn Fein, which hopes for a united Ireland one day, withdrew from a coalition with the Democratic Unionist Party, which wants Northern Ireland to remain part of the United Kingdom.
https://www.nytimes.com/2017/11/20/world/europe/northern-ireland-stormont-adams.html