I happen to believe, all other things being equal, that Northern Ireland could do perfectly well out of the forthcoming UK/EU negotiations. On top of its ability to seek a bespoke deal of its own given its land border with an EU member state and shared citizenship entitlement, it is well used to instability already.

However, it could also do disastrously if “Brexit” is not properly thought through.

The essential problem is an unspoken one. The 1998 Agreement entitles people in Northern Ireland to be British, or Irish, or both; but also it is predicated on making it irrelevant which one anyone chooses. Since both British and Irish citizenship is currently EU citizenship (including an entitlement to use each other’s diplomatic corps abroad, for example), and both British and Irish citizens are effectively treated as “home” citizens in each other’s country (with some exceptions), it really is a free choice.

If the UK leaves the EU, and particularly if it leaves the European Economic Area (the Single Market) and/or the Customs Union, it will then matter which citizenship is chosen. There is a very real risk that the choice of British citizenship will put people at a disadvantage when seeking out opportunities in the EU, including in Ireland; conversely, there is a very real risk that the choice of Irish citizenship will put people at a disadvantage when seeking out opportunities in the rest of the UK. This whole thing will make it matter than Northern Ireland is constitutionally part of the UK in ways in which that status is currently irrelevant. At best, that will make people think again about whether the arrangement agreed to in 1998 (power-sharing in the UK with cross-border bodies) really works for them; at worst, it will lead to an outright schism of Northern Ireland’s population along British-Irish lines, undoing much if not all of what has been achieved over the past 20 years.

The crux of Northern Ireland’s conflict was (and is) identity, and EU membership was central to making it not matter. Doing anything which makes it matter at best risks a precarious balance. Frankly, this is a very good reason for the UK Government reconsidering the whole idea of leaving the EU. The fact is that most people who voted to leave the EU are not going to get out of “Brexit” what they really wanted to get out of it – regardless of what that is. Is it really a good idea, on the basis of a very narrow referendum result, to risk decades of careful work creating a balance which works in Northern Ireland, and thus keeps the whole UK as safe as it reasonably can be from Irish terrorism? It is, at the very least, worth considering whether the desires of those who voted to “leave” can be met in other ways.

If the UK Government decides, as it probably will do for a host of political reasons, that it really must proceed to leave the EU, then the next option is a “soft Brexit”. There would be no harm is emphasising that the constitutional balance of the UK, not least with regards to Northern Ireland, is best served by maintaining as far as possible commonality and mutuality of opportunity between the UK and the EU – and this means retention of the Single Market and the Customs Union. The difficulty here is that, frankly, such a “soft Brexit” would put the UK in a worse position than if it simply remained in the EU. It is unlikely to fly in practice.

The next option is a “Special Status” arrangement for Northern Ireland, and rationally that looks tempting. Northern Ireland alone could remain within the Customs Union; it could even in theory retain up to a point its own immigration policy (uniquely in the UK, it is already the case that employment policy is devolved to Northern Ireland). Alongside mutual recognition specific to Northern Ireland of Health care arrangements, driving licences and perhaps even things such as trading standards and environmental regulations, this would have the effect of maintaining almost all the social benefits of EU membership (albeit, from a Leavers’ point of view, maintaining also almost all the disadvantages). However, it would still be seriously destabilising, because it would mean that British citizens in Northern Ireland would be disadvantaged in certain ways – quite possibly, for example, by being asked for their passport and checked for goods every time they travelled to the rest of the UK. That the DUP would have shosen a course of action which brought this about would not be lost on many of us, but that would be little practical consolation. Did we not just spend decades overcoming that sort of thing?

As with so many aspects of “Brexit”, there is no evidence the UK Government has grasped the scale of the problem here. It will take more than a quick day trip for it to be fully understood, and some time for it to be effectively tackled. It we absolutely must leave the EU, it is vastly more important to do it carefully than to do it quickly.