We are long past the point where any rational person expects the European Union to oppose Donald Trump’s war on Iran on such quixotic grounds as values, morality or law. What’s baffling, though, is the EU’s failure to protect its own naked self-interest. It is sleepwalking into an existential crisis.

Obviously, the primary victims of this war are the Iranian people, caught as they are between a vile regime in Tehran and a mad one in Washington. Next are the people of Lebanon hunted from their homes by Israeli bombers. After that, the damage is inflicted on the wider Middle East, most notably the Gulf emirates whose mirage of dazed detachment from geography has been so cruelly dispelled.

Beyond these catastrophes, though, there is a less immediate but no less fundamental threat to the EU. The United States can (and sooner or later will) walk away from the wreckage of Trump’s war. It’s what it does: the evacuation of Ho Chi Minh City replays itself in the helter-skelter retreat from Kabul.

This is the great privilege of superpower: you get to outsource consequences. If you make movies about these disasters, they are about the pain of your own vets. The rest is just numbers: hundreds of thousands, maybe even millions of deaths and injuries to foreigners that are as forgettable as they are regrettable. As the catchphrase in one military sitcom had it: Oh dear, how sad, never mind!

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But Europe can’t walk away from what may be the threefold after-effects of the violence that Trump calls his “little excursion”. Each part of this unholy trinity of effects interacts with the others to make the overall outcome much worse.

What may well happen is that the US and Israel ultimately succeed in turning Iran into a failed state. The regime crumbles, the country’s infrastructure is devastated, its oil industry is destroyed, a civil war erupts between the remains of the Islamic Republic’s military nexus and various rebel groups, some of them hoping to break up the country and establish their own autonomous ethnic states.

The first consequence for Europe is economic. The current disruption to supply chains and rise in oil and gas prices becomes long-lasting. Stagflation – the dreaded combination of low growth and higher prices – takes hold.

European citizens experience increased distress, with many thrown out of work and many of those in work struggling to make ends meet. Already very fragile political systems come under ever more intense pressure.

The second consequence is terrorist attacks in European cities. The existing regime in Iran has sponsored international proxies, but it has not in general directed them against Europe. (Al-Qaeda and Islamic State are Sunni, not Shia.) But such apocalyptic jihadist groups do arise from failed Muslim states: the implosions of Afghanistan and Iraq tell their own horror stories.

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And then there is a refugee crisis that could well be on a scale greater than anything we have experienced in our lifetimes. Iran’s population is three-and-a-half times greater than Syria’s. The implosion of the Assad regime pushed 1.4 million Syrian refugees into the EU.

Iran is itself already the second biggest host country for refugees: it shelters 3.4 million refugees and an additional 1.1 million Afghans with varying kinds of legal status. If Iran melts down, these people could well be forced to seek safety elsewhere – and that’s before we think of indigenous Iranians fleeing civil war and economic collapse.

The EU’s Agency for Asylum published its annual analysis of trends just before Trump launched his war on Iran. Nonetheless it notes that “even partial destabilisation [of Iran] could generate refugee movements of an unprecedented magnitude”. If even 20 per cent of Iranians were displaced – a very conservative proposition – we would see what “unprecedented magnitude” looks like, both in human misery and, after some time, in pressure on the EU’s borders.

Each of these consequences is dire, but put them together and you have an existential threat to the EU. The equation is not that hard to calculate. Deep economic crisis plus shocking terrorist attacks in EU cities plus an unprecedented wave of refugees equals a dream scenario for the far right.

For the nativist, neo-fascist and ultranationalist forces that are already in the ascendant, all their birthdays would have come at once. The EU as a liberal, democratic and law-bound entity cannot survive the simultaneous capture of most of its member states by far-right authoritarians.

A grotesque irony here is that Trump and his Maga successors would, in this scenario, win a huge political prize. They have made no secret of their desire to destroy the EU and replace it with mini-me regimes in all its former member states (including, of course, Ireland). I am not suggesting for a moment that attacking Iran is part of this dark strategy. It is not part of any real strategy at all – but it could end up achieving this great geopolitical goal nonetheless.

If Iran does collapse into failed statehood, Trump and his ally Binyamin Netanyahu will declare victory, build triumphal arches and present themselves with garish gold medals. The people of Iran and the wider Middle East will pay the price. But so will the EU. Do you think Israel or the US is going to take in millions of Iranians whose lives have been made unlivable by their actions?

All of this is obvious enough. It is not inevitable but it is plausibly predictable. And the least that should be expected of any organisation that doesn’t have a death wish is that it does everything in its power to head off a looming threat to its own life.

What Europe has in its power is relatively limited but not negligible. It can do a lot to put pressure on Netanyahu through trade sanctions. It can act robustly at the United Nations to demand the reinstatement of international law. It can speak truthfully to Trump and, more importantly, to the large majority of Americans who do not support his lethal adventures.

© The Irish Times