WHEN Britons voted to leave the European Union two years ago, they had no chance to say what sort of Brexit they wanted. But Theresa May, who became prime minister in the aftermath of the referendum, quickly decided that they wanted the most drastic break possible. Without consulting her cabinet, let alone Parliament, she announced “red lines” for her negotiation with Brussels that put Britain on course for the fullest of separations.

This “hard” Brexit—in which Britain would free itself from the clutches of European judges, trade policy and migration rules, at significant cost to its economy and security—has long looked inevitable. Parliament’s resistance to Mrs May’s extreme plan has been timid and the Labour opposition feeble. Yet this week the tide turned. Rebel Tory MPs look likely to wrest control of Brexit’s endgame from the government (see Britain section). Meanwhile, the penny dropped among Brexiteers that the Irish border presents a near-insurmountable roadblock to a hard exit. With less than six months of negotiating time left, it is becoming clear that Brexit will be softer than Mrs May set out. That is good news for Europe and for Britain.

U-bend if you want to

This week’s showdown got the government to promise MPs a “meaningful” vote on the deal Mrs May negotiates with the EU near the end of this year. The assumption had been that a vote to reject Mrs May’s version of Brexit would lead to a drastic “no deal” outcome, in which Britain simply left without covering its financial obligations or establishing its future relationship with the EU. That need no longer happen, because Parliament will now be able to force the government to start again.

That still leaves plenty of room for a hard Brexit. Although the negotiations have laid bare the cost of such a policy, the government has stuck to its demands and red lines. Brexiteers bluster that any problems can be overcome with a bit of positivity and patriotism, or argue that they are a reasonable price to pay for freedom from Brussels. They have persuaded the prime minister that the referendum obliges her to take Britain out of the EU’s single market and customs union at any cost.

But there is one area where Britain cannot opt for maximal separation, however great Mrs May’s appetite for self-harm. Brussels has demanded that in Northern Ireland, for the sake of peace, there must be no new checks or infrastructure at the border. Mrs May agreed to this in December, and has since been seeking a way to reconcile an independent trade policy with an invisible, open border. She has failed—unsurprisingly, since even the EU’s most frictionless frontiers, like those with Norway or Switzerland, involve some checks. So Britain will resort to a “backstop” plan, keeping Northern Ireland in the EU’s customs union until it finds a solution to the border problem, which it may never do. To avoid customs checks between Northern Ireland and the British mainland, which would incense the Northern Irish unionists who prop up Mrs May’s government, the customs union will cover the whole United Kingdom. And it will have no firm time limit.

The softening may not end there. Britain has promised that its Northern Irish backstop will include “full alignment” with the relevant rules of the EU’s single market. Again, Mrs May might find that she has to apply this to the whole country, to avoid a unionist rebellion. Britain would thus find itself in a notionally temporary, but in fact indefinite, arrangement that included membership of the EU’s customs union and full alignment with much of the single market. Soft Brexit would have been achieved, via a backdoor in Belfast.

Soft, strong and very long

Though the logic of the negotiations now points to a soft exit, such an outcome is not yet inevitable. Britain’s soft landing outside the EU faces three main risks. The first is that the rest of the EU leaves Ireland in the lurch and drops its demand that the border remain invisible. But EU leaders’ language on the border has if anything been toughening.

The second risk is popular outrage when the EU refuses to give Britain privileged access to the single market unless it allows the free movement of people. If, as seems likely, the EU refuses to dilute this principle, Britain could apply brakes that some member states have already used: registering new migrants, limiting their access to benefits and even excluding them from public-sector jobs. That may be enough to appease some Brexit voters, given that net migration of EU citizens has already fallen more than half since the referendum. Others might be bought off if Mrs May fulfilled other Brexit promises, such as stumping up more money for the health service. And although a hard core would never forgive any softening of Brexit, many more will tune out next March, once Brexit is formally achieved and the blue passports have been issued.

The gravest risk for Mrs May is not the will of the people—polls suggest most Britons favour a soft Brexit. It is the Europhobic wing of her own Tory party. If the prime minister seems to be going soft, her MPs may trigger a leadership challenge. But she might well win such a contest, given the lack of obvious replacements. Even if she fell, her successor would run into the same problem in Northern Ireland. Some Tories complain that the Northern Irish tail is wagging the British dog; they might prefer to see a customs border in the Irish Sea than the wrecking of their hard-Brexit dream. Yet the government’s reliance on unionist votes makes this tail hard to ignore. Would a diehard Brexiteer prime minister risk yet another election, in a bid to win enough seats to ditch the unionists? It would be a reckless gamble that exhausted voters might punish.

The road to a soft Brexit is bumpy. But the remorseless logic of the Irish border is pushing Britain in that direction. And then what? Some Leavers see a soft Brexit as a transition to a complete break. Some Remainers see it as a platform from which to rejoin the EU. Others, from both camps, think that such a semi-detached state is the worst of all worlds. History suggests that Britain might be in for a long stay in transition. Norway, the model cited by many for a soft Brexit, entered a temporary economic arrangement with the EU in 1994. It is still in force.