JUDGES in Britain are not used to being pilloried. So the response to a High Court ruling on November 3rd that the government must have the approval of Parliament before initiating the Article 50 procedure for leaving the EU came as a shock. Several newspapers loudly denounced the judges for trying to subvert the referendum vote for Brexit on June 23rd. No matter that the judgment was not about whether Brexit should happen, but about the narrower question of whether the government could unilaterally invoke Article 50 using its prerogative powers to make and unmake treaties.

On this issue the judges were emphatic. Because the 1972 European Communities Act that gives effect to Britain’s EU membership confers domestic rights on individuals, those rights can be removed only by Parliament. Yet the government still disputes this view. On November 7th David Davis, the Brexit secretary, confirmed in the House of Commons that the government would appeal to the Supreme Court. All 11 justices will hear the case in early December; they are expected to hand down their judgment only in January.

Most lawyers who have studied the High Court judgment expect the Supreme Court to concur with it. The only thing that might change this is if the court questions whether triggering Article 50 irrevocably leads to Brexit. In the High Court case, both sides assumed it would. Yet in Brussels many lawyers believe that, even though Article 50 sets a two-year deadline for a country to leave, its invocation could in practice be withdrawn at any time. Such an argument could help the government to win in the Supreme Court. Yet it does not wish to use this line, because it dislikes any suggestion that Brexit could be reversible. Furthermore, were the case to turn on this issue it could lead to an embarrassing referral to the European Court of Justice.

What will happen next? The most likely outcome is delay, which may threaten the government’s promise to trigger Article 50 by the end of March. If the government loses in the Supreme Court, it will surely have to introduce not a parliamentary resolution but a bill to be enacted by both houses of Parliament.

Most MPs and Lords backed the Remain side in the referendum. Even so, they are unlikely to block the invocation of Article 50. But they may try to attach conditions that the government dislikes, such as demands for more clarity over negotiating goals, a commitment to stay in the EU’s single market, a special arrangement for devolved administrations (Scotland’s government, particularly unhappy about Brexit, has said it may file a brief in the Supreme Court case) or a demand that an eventual Brexit deal must be approved by a further referendum.

Theresa May’s government has a working Commons majority of only 14 seats and no majority at all in the Lords. Yet it should eventually be able to secure a cleanish Article 50 act without many conditions. One tactic it is quietly using is to threaten its opponents that it might call an early general election, which opinion polls suggest could substantially increase its majority. Yet this would itself be a risky course—the pollsters can be wrong, as America found out this week—and would also delay the invoking of Article 50.

The more important debate over Britain’s departure from the EU is about what sort of Brexit is most desirable and what is the best way to negotiate it. On both these questions Brexiteers are being deliberately—and perhaps dangerously—opaque. Thus many are claiming that Britons voted on June 23rd to leave the single market, to impose strict immigration controls and to stop sending any money to Brussels. Yet the question on the ballot paper was only about whether to leave the EU. A clear trade-off exists between the goals of maximising market access and adopting tougher controls on migration. Almost all economic analyses have found that the costs of Brexit to the economy will be far higher if unfettered access to the single market is lost.

The man without a plan

As for how to get the best deal, the government insists that to give more clarity over its objectives would be to tie its hands in Brussels. Mr Davis repeatedly told the Commons that, although he would be as open and transparent as he could be, he would reject demands to disclose the government’s negotiating position. The suspicion must be that the government, riven by internal arguments, has actually not got any such position. But Mr Davis’s argument is that, were it to set out minimum negotiating objectives, other EU governments would immediately make these the maximum that could be secured. One Tory MP likened demands for more parliamentary say to a poker game in which the government has to lay all its cards on the table.

Such analogies betray a fundamental misunderstanding of how EU negotiations work. It is true that the final details are often settled in the small hours and behind the closed doors of a European summit. But almost everything said and done in Brussels is immediately leaked. Moreover, the best outcome to any EU negotiation is, rather like international trade talks, not a zero-sum one in which one side must win and others lose: it is one in which all can see benefits.

In any case, before most crunch summits, national leaders (including British ones) have disclosed to their parliaments and their voters the broad outlines of what they hope to achieve. That is what Harold Wilson and David Cameron did in their attempted “renegotiations” of the terms of Britain’s membership. It is what Margaret Thatcher did in her battles over the EU budget in the 1980s. Other leaders act likewise. The Danish prime minister gets a mandate from the Folketing that he can depart from only by consulting it again. During the euro crisis, Germany’s Angela Merkel repeatedly had to secure the assent of the Bundestag for her decisions.

Mr Davis and his colleagues insist that more parliamentary say over Brexit would reduce the chances of a good deal. But experience in Brussels suggests the opposite: greater transparency and parliamentary guidance would strengthen not weaken Mrs May’s hand. By bolstering Parliament’s role, the judges may have nudged Britain towards a better Brexit.