This article is part of our Britain in Europe series.
It is hard to see what ‘red lines’ could be imposed on the government, but the ruling could be an important victory for thought and reflection over rabble rousing on both sides.
'Take back control', the slogan that won the referendum for Vote Leave, now threatens to take that prize away from them. Or so it seems to Nigel Farage. For him, Thursday's High Court ruling, which asserted that Article 50 cannot be triggered without the consent of Parliament, has all the makings of an establishment stab in the back. Other prominent leavers - including Conservative MP Stephen Philips, who resigned on Friday - argue the opposite: that the promise to 'take back control' was precisely about giving British parliamentarians a say in matters that affect the UK.
Both sides have a point, but Thursday’s ruling will neither block the decision to leave nor grant full parliamentary control over the UK's negotiating position. Most importantly, it does not necessarily boost the chances of a 'soft' Brexit.
Not a victory for 'Soft' Brexit
First, it is still possible that the government will overturn the result on appeal. Thursday's outcome surprised many legal experts and government lawyers may yet convince the Supreme Court that the Crown Prerogative elapses only once the European Communities Act of 1972 is repealed as part of the so-called 'Great Repeal Bill'. MPs will then have the chance to debate at length, but they will have lost the leverage over the Government that the current ruling affords them.
The second possibility is that the Government loses the appeal but manages to 'face down the rebels' in the Commons in time to meet Theresa May’s timetable of triggering Article 50 by March. This could be achieved by passing a non-amendable motion that presents MPs with a binary choice to approve or reject triggering article 50. Assuming that most MPs would not dare to risk the ire of the leave voting public, the Government would then be free to pursue its agenda much as before.
The third option is the most likely. The Government will lose its appeal and be forced to introduce primary legislation– a 'Brexit bill'– that will make it difficult, but not impossible, to meet the deadline. This is likely to force the Government to make concessions to MPs, but not, crucially, in any form that will amount to a commitment to a 'soft' Brexit.
The latter is, of course, what the majority of Labour, the Liberal Democrats, the SNP and a rump of Conservatives now want. The biggest obstacle to this outcome, however, is the lack of unity among this would-be coalition.
Labour MPs around Chukka Umunna, for example, want membership of the Single Market. The SNP want it for Scotland. The Labour leader Jeremy Corybn and his allies have adopted a characteristically counterintuitive position of wanting to retain the freedom of movement without membership of the single market. A few want a second referendum. Keir Starmer, the shadow Brexit minister, talks about membership of the customs union, 'access' to the single market, limiting migrant numbers and ending the authority of the European Court of Justice.
Crucially, among opponents of 'hard' Brexit there is also very little discussion, let alone any consensus, surrounding the price the UK should be willing to pay for its preferred form of membership in terms of acceptable levels of migrant numbers, regulatory oversight, payments into the EU budget, lost Passporting rights or regional funding. In short: the ‘soft’ Brexit MPs do not have a negotiating strategy, either.
In this situation, it is hard to see what formal conditions or 'red lines' could be imposed on the government. Most likely they will either be generic, essentially echoing the Government's call for maximum access with minimum damage; or limited to low hanging fruit, such as insisting the Government guarantee existing employment rights or the rights of EU nationals resident in the UK.
What is clear is that the idea that Parliament will somehow try to force the Government to promise something as dramatic as continued membership of the Single Market or a second referendum, is neither plausible nor feasible. This is important also because it eliminates the scenario in which May, faced with an intolerable limitation on the Government's negotiating posture, would be likely to call a general election. There may be other paths to that result but this is certainly not one of them.
A victory nonetheless
All of this does not mean that the ruling is insignificant. It is an important opportunity to force the Government to divulge more of its strategy– a move that is likely to have cross-party support– and to debate the concerns and priorities of the electorate, including those of Leave voters, before negotiations begin. It is also an opportunity to press for a more open and inclusive process going forward, that expands parliamentary oversight beyond the narrow confines of the Brexit Select Committee.
The important question, though, is: will that make any difference? The Government might merely offer Parliament something to 'bat around' while lawyers, academics and the civil service get on with the huge task of comprehending the negotiations in front of them.
There is scope to be more optimistic, however. Involving Parliament in a process that will ultimately be defined by many complex and cross-cutting trade-offs – such as between free movement and the market, or regional and sectoral interests – might help to dispel the myths of simplistic 'hard' and 'soft' labelling. Nationalist parties would no longer plausibly be able to claim that they are excluded. Most importantly, MPs will be forced to do their EU homework and, seeing that there is no scenario in which anyone will get everything they want, might start to weigh up different options with a little more humility, information, and concern for their constituents.
After a weekend of furious comment, Mark Carney's sober assessment may prove to be the most accurate: this ruling is but one of the many twists and turns we can expect this country to take on the road to Brexit. It is not an opportunity for reversal. It is not in and of itself a victory for 'soft' Brexit. It could, however, be an important victory for thought, reflection, and popular participation – if not 'control'– regarding the most important event in this country's recent history. One can only hope that it will also lead to the victory of realism and a less parochial attitude towards Brexit.
But what remains unchanged and most striking about the current debate in the UK, including over last week's ruling, is the gulf that separates the discussion of the many things we in the UK want from Brexit from what European negotiators are likely to countenance giving us at all.