The Belfast Agreement was not that if the UK ever left the EU, Northern Ireland would stay under EU jurisdiction. But if Ireland & the EU insists that's what it was, then so much the worse for the Belfast Agreement & it'll have to go when we leave the EU.
It oughtn't to have been pressed to this choice, but if Ireland & the EU force it to be, then when push comes to shove, leaving the EU - properly, truly leaving it - is (massively) more important than the Belfast Agreement. It is nowhere near a top Brexit priority.
Almost everyone's tried to avoid saying, up to now, that the Irish border is not a top priority. No-one wants to be responsible for any future unrest or lawlessness. But it is the blunt truth. What happens at the Irish border is far less important than that we truly leave the EU.
I don't believe there need to be stop-&-check controls at the Irish border, but I am not prepared to see any compromises on anything fundamental to avoid them. Avoiding them (especially insofar as they are implemented by the EU not the UK) simply isn't that important.
