Brexit may, it turns out, not mean Brexit.

On Thursday, the U.K. High Court judges put the experts back in control of the Brexit process, giving lawmakers the final say over whether the country actually follows through on its referendum vote to leave the EU.

There is now a much stronger chance that the Brexit process will be substantially slowed down, watered down, and even, maybe, reversed.

The pound rose by 1% against the dollar on the news, consistent with the view that it cuts the chance of a ‘hard’ Brexit that leaves the U.K. unwilling to attract skilled migrants and unable to sell its financial services and exports freely to its biggest and nearest market.

Sterling would have risen more, but there is still enough momentum behind the Brexit process to keep the euphoria in check.

Firstly, Prime Minister Theresa May’s government will appeal in the Supreme Court on December 7 (a date that already lives in infamy and must be wondering what it did in a past life to deserve this).

Secondly, the High Court didn’t say what kind of approval from parliament would be needed. May, at pains to stress her commitment to delivering the referendum mandate, could try to argue that a simple debate and non-binding vote would be consultation enough. But it’s more likely that the government will have to draft actual legislation before invoking Article 50 of the EU’s treaty, formally notifying the other 27 member states of the U.K.’s intention to withdraw.

It’s not that MPs are likely to stop May triggering Article 50, even though around three-quarters of them voted to Remain. They’re too afraid of being accused of ignoring the will of the voters for that.

But drafting, revising, debating and approving legislation all takes time. If the process only starts in January, after the Supreme Court hearing, then–according to Jolyon Maugham, one of the lawyers who brought the case to the High Court–May can give up any hope of activating Article 50 by March. That was the deadline she had recently promised to keep to.

Then there is the question of what conditions, in the form of amendments, parliament might make to any proposed legislation. It could insist on knowing the government’s final preferred outcome from the outset: Should the U.K. remain in the Single Market, to minimize disruptions to business? Or should it stay outside, in order to escape the jurisdiction of the European Court of Justice and to allow tighter immigration controls? (Business prefers the former, May has indicated she prefers the latter.)

Parliament could also hobble the government’s negotiating strategy. Susan Bright and Charles Brasted, partners at law firm Hogan Lovells in London, argued that “the Government has thus far been keen to avoid giving a running commentary on its proposed negotiations with the EU, but it will inevitably be pressed to open up its proposed negotiation terms to Parliamentary scrutiny in light of the decision.”

Most significantly, parliament could insist on ratifying or vetoing the separation deal that the government and EU finally hammer out. It could even require a second referendum. The benefit of such a course would be to allow a more informed decision than the one Britain made on June 23, when nobody knew with certainty what life after Brexit would look like. A second, confirming vote would greatly enhance the legitimacy of the first one, or represent an equally legitimate withdrawal from an initial position taken on a very imperfect understanding of what would follow.

Unsurprisingly, supporters of Brexit such as former UKIP leader Nigel Farage are incensed by the court’s ruling. In an acute irony, politicians who had complained for years about how British courts should decide how the British people are ruled are now complaining about those very courts exercising their prerogatives.

Former Justice Minister Dominic Raab, a Conservative, told the BBC the High Court had opened “a can of worms” and said he “hoped the Supreme Court will put a lid back on it.” Such views are widely shared by Britain’s tabloid press. The pro-Brexit (and anti-pretty much everything else) Daily Mail was more blunt, tarring one of the three judges as an “openly gay ex-Olympic fencer.” That’s the sort of disgusting scum blocking the Will of the People, you see.

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The ruling certainly touches a raw nerve, blunting the force of what was widely seen as a revolt of the left-behind against an establishment élite (even though the people who really delivered the referendum mandate were cosseted pensioners).

One last thought. When the Supreme Court rules on the government’s appeal, it will have to consider whether the mere triggering of Article 50 actually starts an irrevocable process. If it does, it would constitute a de facto overturning of the European Communities Act of 1972, and an Act of Parliament can only be unmade with another Act of Parliament (forcing the government to prepare legislation). The text of Article 50 makes no provision for reversing the process, but nor does it explicitly say that a country has to go through with the act of leaving. EU Council President Donald Tusk, for one, plainly believes that it doesn’t. The only court that can say what the EU Treaty means in reality is…the European Court of Justice in Luxembourg.

Law, and due process, is what stands between majority rule and dictatorship. It’s the very essence of what Britons think makes their country special. Given the inability of the government to explain in any detail what the vacuous phrase “Brexit means Brexit” means, it ought to welcome the structure and discipline that parliamentary scrutiny brings.

But if the Supreme Court ends up referring the case to Luxembourg, then we will truly have reached Peak 2016.