NI is part of NATO too, as part of UK. UK is obliged under international treaty to respect the EU customs border down the Irish sea, so if they refused to respect the treaty they would be in breach of international law. I don’t think NATO would want to be involved.
Gove’s recent remarks were staggeringly irresponsible, and you can’t blame the Irish (and EU) if they are indeed making contingency plans. They would be perfectly entitled to enforce the treaty, and the majority of NI (not all albeit..) would support them.
Last edited by Trim Stab; 29th Jun 2020 at 18:43.