With just two weeks to run, the referendum debate in the United Kingdom has backed itself into a cul-de-sac with far too much emphasis on narrow economic issues. The Remain supporters, led by David Cameron and his chancellor George Osborne, have focused on the downside to EU exit, citing various estimates of short- and long-term damage to the UK economy.

Mortgage costs will rise, take-home pay will fall and jobs will be lost. Very precise calculations of the damage are being offered. While there should be little doubt that the impact will be negative, the precision in the estimates is spurious: nobody knows just how much damage will be done. After all, there is simply no precedent for a major country exiting a fully integrated trading bloc like the European Union.

The Remain campaign has left itself vulnerable to accusations of fear-mongering and the public is beset with a cacophony of conflicting claims and counter-claims which it cannot evaluate.

The Leave campaigners have chosen to major on the immigration issue. One prominent Eurosceptic has been asserting that the 450 million non-British residents of the EU are free to move to the UK under current rules and could not be denied entry. This is indeed the case and has been for 40 years.

Chaotic migrant flow

For some strange reason continental Europe has managed to retain its population and has not been abandoned as the world’s largest wildlife reserve. Another Leave enthusiast has drawn attention to the threat posed by the (unlikely) accession of Turkey to the EU and the 80 million potential migrants represented by the total population of that country.

Should Turkey join, you are to believe, the entire population – men, women and children – will promptly up sticks and desert the eastern Mediterranean for the delights of the wet and windy north Atlantic.

Europe’s current problem is not labour migration inside the European Union, which proceeds at modest rates in response to relative economic performance. The far more serious issue is the chaotic migrant flow from the Middle East and north Africa into southern Europe, which Britain and Ireland have been spared.

The extent of the economic impact of Brexit is simply unknowable

The extent of the economic impact of Brexit is simply unknowable: it will be negative, since the unravelling of such a comprehensive single market is bound to impose costs, but it is impossible to put convincing figures before the public.

A decision to leave two weeks hence would be followed by a two-year negotiation of the divorce terms and that could go well, minimising the impact, or badly, creating widespread economic dislocation. The optimism of the Leave campaigners about this process is just an expression of faith. They could be right and the economic costs might be contained, or they could be seriously mistaken. On the narrow economics, a vote to leave is a gamble that these negotiations go smoothly and to Britain’s satisfaction. But there can be no guarantees and a messy, and costly, divorce is just as likely.

The real issue is not the hard-to-measure economic costs. With luck these could indeed be modest as the Leave campaigners optimistically argue. But the European Union is not just a trading bloc – it is the principal expression of the post-war European political settlement, along with the defence umbrella provided, largely at American expense, by the North Atlantic Treaty Organisation. If Britain departs the EU it may not be the last country to do so and the political order in Europe could begin to fracture.

Eurosceptics

There are growing Eurosceptic parties in several EU member states and they will be emboldened if the UK opts to quit. The leader of the UK Independence Party, Nigel Farage, openly welcomed this prospect in a newspaper interview reported on Monday last. Farage expects a British vote to exit would be the first step in the disintegration of the European Union and cheerfully cited this outcome as his motivation for supporting the Leave campaign.

It borders on the heroic to assume that a new political order in Europe can effortlessly be whistled up in the atmosphere of recrimination and instability that would follow the demise of the European Union.

This is the greatest threat to both the UK and Ireland when the voters go to the polls. A victory for the campaign to leave will signal that one of Europe’s key nations has given up on Europe and concluded that the existing institutions are incapable of reform. That they need reform is hardly at issue but it is less rather than more likely that reform will follow a British exit.

Ireland has never been in membership of these institutions without the UK and the institutions will be weakened, perhaps fatally, if the British leave. Irish politicians and business figures are to be applauded for supporting the campaign to keep Britain in Europe.

Colm McCarthy on Brexit: no one can say how bad the damage will be

There is simply no precedent for a major country exiting a fully integrated trading bloc like the European Union.