The U.K. and the European Union are still trying to work out a deal about what happens to Northern Ireland after Brexit. It's not going well.
Prime Minister Theresa May told the U.K. Parliament, "No U.K. prime minister could ever agree to it."
The problem is the land border between Northern Ireland and the Republic of Ireland. It's barely noticeable now because both regions are currently part of the EU.
But when Northern Ireland leaves the European customs union with the rest of the U.K., it'll likely end up with different trade rules and regulations. That means it could need to set up a hard customs border with the EU.
The latest Brexit proposal from the EU draws the customs border between Northern Ireland and Great Britain. That's a non-starter for the U.K. because it effectively splinters Northern Ireland from the rest of the country.
But the other obvious option — Northern Ireland setting up a hard border with Ireland — could jeopardize the Good Friday peace agreement, which has kept the two regions from bloody conflict for almost 20 years.
May could get around this issue by keeping the entire U.K. in the E.U.'s customs union, something opposition leader Jeremy Corbyn recently called for. But May's government has already ruled out that idea.
May's only other option is to find some sort of special technological solution that respects the different EU-U.K. customs laws while keeping the Northern Ireland border open. That solution has yet to materialize.
