After the United Kingdom’s unexpected vote to leave the European Union and Donald Trump’s unexpected triumph in the US presidential election last year, you might imagine that Europe’s chancelleries have developed detailed contingency plans for a victory by the far-right National Front’s Marine Le Pen in France’s presidential election. You’d be wrong.

The thought of President Le Pen is so terrifying, it seems, posing such a threat to the future of Europe, that it remains for many a possibility they dare not entertain, much less plan for. But that threat is precisely why Europe must address seriously the possibility of her winning, however unlikely it may seem.

There is no doubt that, as President of France, Le Pen could do serious damage to the European project. She has positioned herself as the antithesis of German Chancellor Angela Merkel, and pledged to leave the EU’s border-free Schengen Area and the eurozone. As for the EU itself, she promises to follow in the UK’s footsteps, renegotiating the terms of her country’s membership, and then calling a referendum on the agreement. If the EU rejects the reforms Le Pen demands, she will campaign for a French exit.

But there would be important differences between Brexit and Frexit. Whereas many UK Euroskeptics envision a global Britain trading with the world, Le Pen wants to introduce protectionist policies. In lieu of openness, Le Pen—who now casts herself as a Gaullist—wants to deepen ‘great power’ relations with Russia and the United States, as she focuses on defending ‘traditional’ Christian values and fighting terror in the context of a multipolar world order.

To support those objectives, Le Pen promises to increase French defense spending to 3% of GDP (the NATO target is 2%), while making it clear to voters that none of that spending would support stabilization missions in Africa. In this sense, a Le Pen victory would amount to a rupture not just with the European mainstream, but also with France’s strategic orientation over the last few decades.

To be sure, opinion polls still favor the independent centrist Emmanuel Macron in a second-round run-off. But many fear that Macron’s supporters will not be as inspired as Le Pen’s to turn out to vote.

In fact, in recent months, Le Pen’s popular support has remained rather consistent, with her lead in opinion polls for the first round remaining stable, even as French politics is thrown into upheaval by scandal and mistrust. This perfect political storm has caused France’s two-party system to fragment into a four-party arrangement and has all but knocked the favourites out of the running, while leaving Le Pen largely unscathed.

The reasons for Le Pen’s rise have as much to do with her reinvention of the National Front as with the external political environment. She has managed to escape the extreme-right ghetto, with a grand strategy, shaped by her ally Florian Philippot, that aims to broaden the Front’s appeal to key groups that previously avoided it, especially civil servants, women, and Catholics.

As Philippot has advanced this plan, claiming that the National Front is ‘neither left nor right,’ he has also been working to lay the groundwork for a Le Pen-led government. To this end, he is seeking to build a new political elite to serve in a National Front government and help overcome resistance to the party’s agenda from France’s ‘deep state.’ And he has been exploring what the president can and cannot do—including calling referenda—without permission from parliament.

Compared to Le Pen and her team, Europe’s leaders seem woefully underprepared. Of course, with so many unknowns, there is a limit to the plans they can share publicly; indeed, at this stage, specific statements may even prove counterproductive. But that does not mean that EU leaders should simply warn that a Le Pen victory would spell the end of the EU and leave it at that.

Instead, EU leaders should be considering to what extent they would be able to work around a Le Pen presidency. Even if she wins, she will struggle to gain a parliamentary majority, meaning that she may well end up in what the French evocatively call cohabitation with a hostile parliament and prime minister. Would other EU leaders be able to form an informal coalition with those elements of the French government?

Europe’s leaders must also begin thinking about how they should respond to Le Pen’s request to renegotiate the terms of France’s EU membership, and to what extent they should resist her efforts to remove France from the rest of Europe. Should the European Commission develop its own plans for a French exit from the eurozone and Schengen?

There may even be a case for Europe’s leaders to facilitate France’s withdrawal from the EU, lest Le Pen attempt to dismantle the EU from within, by building alliances with the likes of Hungarian Prime Minister Viktor Orbán. It is certainly a possibility that must be considered.

To say that these are difficult questions is an understatement. But that is precisely the point: bringing them out into the open demonstrates just how disruptive Le Pen’s victory would be. Indeed, from the EU’s perspective, a hostile president in France, the country of Jean Monnet, would be far more destructive than Brexit.

If we have learned one thing from the annus horribilis that was 2016, it should be that opinion polls are fallible. Rather than shut their eyes and hope that, this time, the pollsters are vindicated, the EU should prepare even for the worst-case scenario. Such plans may never have to be implemented, but Europe’s leaders should make them now, rather than wishing later that they had.