Putting a border in between Northern Ireland and Ireland would at the least risk the GFA. Avoiding it by moving Northern Ireland out of the UK simply moves the border to between Northern Ireland and the UK, which still risks the GFA, it just pisses off a different set of people, and more of them.
Interesting. I hadn't expected that.
It's a good question, and one I've mentioned before in this thread.
Ultimately the position is that the EU will insist on a hard border to protect its customs union and workforce (as is its prerogative), but the EU didn't sign the GFA. Essentially as it's the United Kingdom's change of laws that created the situation that necessitates the border, the UK would be in breach even if it just ignored the border altogether - although I imagine that wouldn't play well with either the EU (which would likely take the UK to international courts over it) or with the TaKe CoNtRoL oF oUr BoRdErS Brexit voters.
Yea, I don't see how the UK is in breach of anything just by withdrawing from the EU, and it definitely seems like RoI's responsibility to handle border control since it's an EU demand for that country. Did the UK agree to set up customs checkpoints at every border if it withdraws from the EU? Because that seems... unlikely... to me. Without that in place, I'm not sure what the UK would be in breech of.
The DUP would go absolutely ape-faeces ballistic, but, in the height of irony, that solution would leave Northern Ireland in a ridiculously strong position of being inside the UK single market and the EU single market,
Yea, seems like a great win for NI (and kinda for the UK too actually).
which (ironically) would make the Scottish Nationalists go nuts because NI would have a massive economic advantage over the rest of the UK...
Seems like they'd need the deal too.
But, while in Ireland that would prevent a hard border (between NI and ROI), for Scotland it would probably mean erecting one (between Scotland and England), as the EU would require any border between it's Single Market area and a non-Single Market area. It is doubtful that either the EU or the UK would accept such an arrangement.
Except that you get one in the case of independence too. Either way there's a border with the EU, it's just that in one case Scotland gets the special EU/UK market bonus along with NI.
Technically we're not, but the UK requires a trade deal with the EU and the EU will not play ball unless the UK does what it wants us to do.
I think the UK should accept that the EU is not playing ball and will not until they take the UK seriously. Hard brexit, don't control the NI border, see what happens.
(probably Scotland goes, but, that seems hard to stop).
Edit:
BTW, with regard to a lack of border control into the UK via NI, I think that the UK can still catch folks bypassing regulations even without customs. I guess the concern is not security so much, because right now the UK is trusting RoI to handle that on that border as it is. That part doesn't change. Anyone coming into RoI can get into the UK today, so if that's the case after a hard brexit with no NI border, nothing has changed.
In terms of taxes, the US has some experience with different taxes in different areas where there is no customs control. Oregon, for example, has no state sales tax. California does. So if you buy a product in Oregon you can get it 10% cheaper than California. The two states share a border and, though I did say some inspection happens, ironically it does not happen to catch sales tax cheats.
Companies don't cheat the system because they want to maintain a business operation license and not be taken to court by states and bankrupted. Individuals also have trouble pulling off the cheat because you'll get caught one way or another. I'm not going to say it doesn't happen, it definitely does, but it's marginalized, despite a 10% price difference and no customs.
Edit 2:
I guess technically the CA state sales tax is 7.25%, but for all residents of LA for example (I don't know about SF, but that seems likely too), it's 10%.