We are in a moment of great peril. The invisible infrastructure that allows life on the islands of Ireland and Britain to function as it does could shut down in just over 100 days.
It is impossible to predict whether there could be shortages of imported goods, how serious those shortages could be and how long they might last. But there are real risks of major disruption to trade across the Irish Sea in the event of a no-deal Brexit.
While the trade and economic issues around a no-deal Brexit are highly uncertain, there is less uncertainty about how such a rupture would affect relations among the peoples of these islands.
It is imperative that nobody has to find out how bad things could get. If Britain does not agree to the terms of departure on offer from the EU and proceeds toward a no deal, the Irish Government should rethink its position on the backstop to avoid the worst possible outcome for everyone.
This would not be easy. One of the many reasons that putting the backstop on the negotiating table was a miscalculation was because it has - inevitably - become politically totemic.
No elected representative publicly opposes it and the media has embraced it, asking few questions about what is one of the biggest foreign policy decisions in this State's history. Unless the national mood and the national conversions change, taking the backstop off the table will be difficult if not impossible for the government.
If the conversation is to change, alternatives will need to be put forward. Here are three.
Last September this column suggested holding a referendum in Northern Ireland on which single market and which customs union people there wanted to belong to (these choices are, alas, binary).
Recent polling by LucidTalk suggests that there is a solid majority for staying with Ireland and the EU, with almost all those identifying as nationalists backing that choice and a third of unionists doing so.
If the people of Northern Ireland were to vote as this poll suggests, the British Government would have cover to go along with it and, as the border issue would disappear, there would be no need for a backstop tying all of the UK to the EU's tariffs on goods imported from the rest of the world.
A referendum in Northern Ireland would have many drawbacks. Most seriously, it would heighten tensions between the two traditions. But given that there is some support among unionists, particularly in the business community, it may not be as divisive as might have been expected just three months ago.
Another option that needs consideration is customs checks only on the Republic's side of the border. That is because, if there is no deal, Ireland will be faced with the choice of putting up customs posts on the southern side of the border or ceasing to be a full member of the EU's single market.
Ireland's place in the European single market is what attracts foreign companies here. Any question about full and permanent participation in it would raise questions for companies currently based here about their continued presence. It would also rapidly and seriously lessen the attractiveness of Ireland for companies considering where to base their European operations.
While nobody wants a border and there is deep and wide opposition to any infrastructure on either side of it, clarity is needed on the consequences of choices that may have to be made.
The Republic's entire economic model would be imperilled by exclusion from the EU single market. It is worth pointing out a united Ireland, which is looming into view, would be less likely if the Republic's economy were once again to become a backwater.
In return for removing the backstop provisions from the withdrawal agreement, Ireland and the EU could seek legally binding commitments from London that no infrastructure would ever return to the northern side of the border.
Another concession that could be sought in return for removing the backstop is a greater role for the Irish government in Northern Ireland. If any kind of border goes up, no group would be more affected than nationalists in Northern Ireland.
EU membership gives a non-British dimension to the governance of the North. Brexit will reinforce the nature of Britishness of governance at a time when British politics is evolving in a way that can be viewed only as threatening, if not plain dangerous, by nationalists.
It is of course possible that the Irish-EU hardball backstop tactics end up causing Brexit to be abandoned altogether.
Talk of a second referendum is growing and the decision of the EU's highest court last week - that Britain could unilaterally withdraw its notice to leave - gives cause for hope to those on this side of the Irish Sea who believe Brexit is madness.
But it will be a close-run thing. As one Irish official told Bloomberg: "This will either turn out to be an incredible diplomatic triumph by Ireland or a strategic mistake."