I know little about Irish history, so this question could be very naive.
Ongoing Brexit negotiations appear to be encountering a lot of problems concerning the Northern Ireland-Ireland border. Why? From my point of view things look pretty obvious:
- Northern Ireland decides whether it's part of the UK or part of Ireland. The obvious way would be to have a referendum similar to the Scotland independence referendum several years ago.
- If it decides it's part of the UK, then its border with Ireland would be like any other border in the world.
- If it decides it's part of Ireland then it should leave the union with Scotland/England/Wales and form a union with Ireland instead (and remain in the EU).
- Or it could declare independence I suppose, and then negotiate whatever it wants with Ireland.
However, #2 looks like something very hard to do and nobody is willing to accept, including both UK and EU negotiators. Why? It sounds so simple: if Northern Ireland is part of the UK, then it ought to act in solidarity with the rest of its country and have a border. If Northern Ireland is part of Ireland, then it ought to act in solidarity with the rest of its country and remain in the EU. It seems to me the problem is coming because Northern Ireland wants to be part of both countries, but that sounds like wanting to have the cake and eat it to, which surprisingly both EU and UK leaders aren't viewing as childish.
Generally the sources I've seen have mentioned the "Good Friday Agreement" and how having a hard border would lead to violence, and I don't see why that would happen either. Scotland had a leave/remain referendum and it didn't lead to violence; why can't Northern Ireland do the same?
I'm asking this here because although this question is deeply tied to politics, I suspect the answer has more to do with history, in particular what exactly is causing the rest of the UK to treat Northern Ireland separately, and why Northern Ireland doesn't view following the rest of the UK as a given thing.