Irish nationalists are missing a trick by portraying Brexit as a terrible calamity. What they should be doing is comparing it to the transition to a united Ireland.
Brexit may well be a calamity, but it is hardly the end of the world. Expert assessments of its worst-case scenario are strikingly similar to unification’s likeliest scenario, namely, a decade or so of recession, confusion, disruption and argument, followed by a return to the long-term growth trend.
In the case of Brexit, the Institute for Fiscal Studies reckons this will happen by 2030, by which time the UK will have permanently lost 4 per cent of GDP.
In the case of a united Ireland, a 2015 study by Canadian academic Prof Kurt Hübner predicted a permanent GDP boost within eight years of 4 per cent in the North and 1.2 per cent in the South.
As with global warming, these apparently small numbers represent big changes. In per capita terms, 4 per cent of GDP is the difference between Japan and New Zealand. Unlike global warming, however, the effects would scarcely be perceptible. A 4-degree rise in temperatures would flood Dublin, Belfast and Cork (and Galway, if that matters.)
A 4 per cent change in income for the average employee in Northern Ireland represents about £1,000 (€1,110) a year in today’s money. Spread that over one or two decades and it comes to £50 to £100 a year, up or down, hidden within inflation and general technological progress.
Who would even notice this? The usual answer would be those who lose their jobs, as a GDP drop tends to manifest itself as unemployment for some, rather than wage cuts for all.
But any economic downturn from Brexit or a united Ireland would not be a typical recession. It would be a much longer and deeper adjustment, meaning its impact on employment should be far less lumpy.
Job losses
There will still be victims: Brexit looks hopeless for farming and food processing, while Hübner anticipates that there may be thousands of public sector job losses in the North.
However, the dislocation would be nothing on the scale of Latvia's near-overnight loss of a fifth of its GDP in 2008, to cite another example nationalists missed. Roughly the size of Northern Ireland and suffering a loss similar to Belfast's subsidy from London, Latvia fully recovered within five years.
This is merely comparing the economic experiences of Brexit and unification. That comparison is important because the Scottish independence campaign has shifted the Irish debate firmly on to these grounds.
Hübner's study was commissioned by Sinn Féin as part of this new numbers game. Delightfully, it assumes Gerry Adams turns into Margaret Thatcher the moment he is in charge – which is a not entirely implausible prospect.
Before that, Sinn Féin used to claim the UK subsidy to Northern Ireland was wrongly and even deliberately exaggerated by a factor of two or three, although only its most credulous supporters ever took this seriously.
But in the end, is money really a decisive factor in something as profound as national identity? The Republic went through boom and bust without allegiances notably changing either way. Northern Ireland has been on economic life support since the 1970s, but unionist convictions have not faltered.
Political flux
Perhaps what Brexit can best provide to the nationalist cause is the lived experience of constitutional uncertainty without the sky falling in.
We are already witnessing a whirl of political flux and speculation across Britain and Ireland that makes the Belfast Agreement look like a minor matter of local government reform and the Anglo-Irish Agreement look like the convening of a sub-committee.
The memory of the Troubles has linked this sort of change to violence in our minds. Brexit could be a chance to break that association.
Instead, Sinn Féin and the SDLP risk emphasising the association. They both insist that Brexit means change on a fundamental constitutional level. Addressing the Ulster Unionist Party conference two weeks ago, SDLP leader Colum Eastwood said: "The United Kingdom as you have known it, as we have all known it, is no more."
Sinn Féin has directly linked Brexit and Irish unity by calling for a Border poll.
Yet both parties also seem to be warning of trouble ahead. Eastwood has said of Brexit: “Northern nationalists are once more a restless people.”
Sinn Féin speaks repeatedly, if vaguely, of a threat to the peace process.
This is no way to refer to a transition comparable to the one you want to put unionists through – and must persuade a number of unionists to support.
If would be better and almost certainly more accurate to say that the United Kingdom is no more, but only settled, peaceful and ultimately painless change is expected.
If any lesson is to be drawn from Scottish nationalism, it should be that.