The Northern Irish Riddle Giving Brexit Negotiators a Headache

One of the riddles of the Brexit negotiations is the rights that citizens in Northern Ireland should have after the U.K. leaves.

As part of the 1998 Good Friday Agreement that brought peace to Northern Ireland, British nationals living there are also entitled to Irish (and by extension EU) citizenship -- even if they’ve never set foot south of the border. While unusual, that was straightforward enough when both countries were in the EU. Now it opens up a legal and political minefield.