In March 2017, the EU's chief Brexit negotiator Michel Barnier was standing in a field in South Armagh, just above the border between Ireland and the U.K. province of Northern Ireland. Peter Sheridan, his host, pointed into the distance and asked: "You see the border?" To which Barnier replied, "No, where?"
"That's the idea," Sheridan said.
The "Irish question" has emerged as an intractable thorn in Brexit negotiations. U.K. Prime Minister Theresa May faces a momentous day in Brussels on Monday — the EU has given her government until December 4 to "put a final offer on the table" for a solution on the future of the Northern Irish border before any trade talks can proceed.
Uncertainty over a potential hard border between Ireland and its northern neighbor has evoked memories of a darker time before the signing of the 1998 Good Friday Agreement, which ended large-scale sectarian violence in the border region and allowed for the free movement of people and goods.
The U.K. wants to exit the EU customs union, taking Northern Ireland along with it, something many fear cannot be done without the imposition of a physical border. A cornerstone of the EU, the customs union exempts EU member states and select outside territories from paying customs duties on all goods traveling within the union.
Concerns about renewed sectarian tensions and political divisions surrounding a possible border are now front and center.