Zack and Jenn are joined by Jen Kirby, one of Vox’s foreign affairs reporters, to discuss what has emerged as the biggest hurdle to the Brexit process: the border between the Republic of Ireland and British-controlled Northern Ireland. They go back in time, starting with the 1920s and going forward to the Northern Irish conflict known as “the Troubles,” to examine the reasons why keeping the border between Ireland and Northern Ireland open is so important. They explain how Brexit threatens to close the border, and how this issue is derailing the entire Brexit process. Zack notes that people don’t like walls, Jenn says the phrase “totes not renegotiate,” and Kirby blasts the “butterflies and unicorn” vision for Brexit.Jen Kirby recommends this wonky deep-read on the backstop.Here’s more on Gerry Adams’s role in the Troubles and the allegations that he was directly involved in the IRA’s violent activities … and here’s more on his forthcoming cookbook. Our explainer of the historic vote down that Jen Kirby mentioned … and our episode breaking down that historic vote.Jen’s piece on this comes out soon!