Britain's Prime Minister Theresa May and France's President Emmanuel Macron hold a news conference at the Royal Military Academy in Sandhurst, Britain, on January 18, 2018Stefan Rousseau / Reuters

Few places in Europe can match the beauty of the Côte d’Azur’s Fort de Brégançon, the French president’s summer retreat. With its rocky shore, lined with coves and pine trees, it’s a Mediterranean paradise. But it may well be on this idyllic coast where Theresa May’s hopes for a soft Brexit and the future of her premiership run aground.

Today, Emmanuel Macron, the president of France, will meet with the flailing British prime minister at Fort de Brégançon to discuss Britain’s troubled plans to exit the European Union next year. May has staked her future on the so-called Chequers plan, a vision of Brexit that would see her government establish a half-in, half-out relationship with the EU’s single market. Yet this plan has already been rejected by Michel Barnier, the European Commission’s French chief negotiator, for the threat it poses to the bloc’s single market, which allows for the free movement of goods, capital, labor, and services across the bloc. Refusing to admit defeat, May believes she can change Macron’s mind through a direct appeal. With Downing Street claiming Angela Merkel is softening on Brexit, May sees Macron blocking her way.

The meeting at Brégançon, which was fortified during Napoleon’s reign, is likely to dash May’s hopes. Embattled by scandal and plunging ratings, Macron believes he is fighting a battle to protect the EU’s very existence against the very same populist forces he defeated in the 2017 election. This has only hardened his attitude to Brexit at the very moment the survival of May’s plan hangs in the balance.

For the first time in centuries then, a French leader has the chance to either throw a British prime minister a rope or cut her adrift. The stakes for Britain could not be higher: Its decades of membership in the EU mean that leaving the single market would severely disrupt its economy. Its supply chains are so integrated with Europe’s that simple “third country” border checks on goods imported into the country would cripple entire industries built on “just in time” deliveries of components from the Continent. This is why May is desperately seeking a compromise that would allow Britain to stay in the single market just for goods. But the EU’s position—that Britain should accept the full terms of single-market membership, including the free movement of labor—has effectively ruled out the Chequers plan.

Britain’s Gordian knot is May: She promised to implement the result of the 2016 referendum, explicitly interpreting it as a demand to end free movement. Downing Street has warned Germany and above all France that compromise is necessary to stave off a potentially catastrophic “no deal” Brexit. Such an outcome would see Britain crash out of the bloc without an agreement, throwing havoc into complex supply chains, border crossings, and financial flows across the Channel. To many in Paris, this sounds like blackmail.

But May appears to have little chance of convincing Macron to back the Chequers plan. Those familiar with his thinking have told me he views the threat to the single market stemming from any breakup of the EU’s cherished “Four Freedoms”—the free movement of goods, capital, services, and labor—as existential. Britain must accept all of the Four Freedoms, including the free movement of labor, if it wants to preserve the free movement of goods, those familiar with Macron’s thinking have told me. This, they said, is because Macron feels that the EU is too fragile to offer Britain a special deal allowing it to cherry pick which one of the Four Freedoms it wants.

France’s own populist menace plays a role here. British officials have failed to grasp that Macron views the EU’s redlines against Brexit as a necessary warning to anyone else wishing to break up the bloc—as a means of dissuading anyone at home from thinking Frexit is even a remote possibility. For Macron, being tough on Brexit is being tough on Le Pen. Conversely, a flurry of his opponents on the right who want to undermine the European Commission have called for a compromise.

Despite this, British officials have frantically pointed to the precedent of Switzerland, or the Channel Islands, or the EU’s own backstop plan for Northern Ireland, where compromises on the Four Freedoms have been made, to suggest that the Chequers plan could work. French officials, just like Barnier, continue to dismiss these ideas, politely reminding the British that the EU chief negotiator is not his own free agent, but the representative of the EU’s member states. In an ominous statement yesterday, the Élysée emphasized that the Brégançon meeting was not a negotiation and no substitute for talks with Barnier.

Macron, if anything, has talked much tougher than Barnier. The French president has previously said he believes in a “hard Brexit”—if Britain goes, it should leave the European club entirely, and retain none of the privileged access to the single market that members enjoy. He wants Britain to choose either free trade from outside the single market, like Canada, or membership fully inside it as part of the European Economic Area, like Norway. Bespoke, half-in, half-out, measures like May’s plan violate France’s interest, he believes. Chequers seeks to dodge the impossible choices: A simple free-trade area would throw up enough barriers to severely damage British industry, while remaining in the single market would mean retaining freedom of movement with the EU.

Yet if Britain wanted a free-trade deal, it would still need to resolve the vexing question of a “hard border” in Ireland. Ever since the peace agreement that ended the long running conflict in Northern Ireland, the border between the North and South has been open. But Britain’s departure from the EU single market would break the single economic area on the island and restore border controls. With Ireland insisting that a hard border would violate the peace agreement, the EU has said it can only agree to a Brexit deal that avoids the reimposition of border controls. The Commission has said that the only way to avoid this and to give Britain the free-trade area it wants would be by creating a “backstop” situation: a customs border between Northern Ireland, still inside the single market, and the rest of the United Kingdom, stretching across the Irish Sea. Any British government and the loyalist community in Ulster, however, see this as unacceptable.

But for all Barnier’s tough talk, Irish officials worry that if Macron decides to make concessions, it will be on Irish—not French—core interests. An op-ed published on Thursday by Barnier in 20 European newspapers offering to “improve the text” of his Irish backstop proposal drops a heavy hint.

While the British government’s terrible management of Brexit has drawn chuckles from Macron’s confidantes, back at the French foreign ministry it has elicited surprise. “We expected the British to be able to divide the EU,” one senior diplomatic source said. “But the fact they were unable to articulate what they wanted meant they failed.”

Macron’s views on Brexit have not changed since I profiled him in April 2017. Then, he told me: “My hope is that we can bring a lot of rigor to managing Brexit, anchoring Britain in a strategic partnership—in particular in the military dimension—while allowing no weakness when it touches on matters affecting the integrity of the union or the durability of the project.” Those familiar with Macron’s thinking insist he still believes this—that he wants both France and the EU to form an ambitious alliance with Britain. But can France have its cake and eat it too?

If forced to choose, Macron would choose EU stability. “He believes in the West,” one senior diplomatic official said. “But future ties cannot come at the expense of the integrity of the EU.” For Macron, there is nothing else but a Europe that can defeat populism. Failure is not an option—at least for him.

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