Henry Newman is Director of Open Europe.

The Brexit options are narrowing. Yesterday evening, Parliament gave a definitive verdict against No Deal. While nothing has yet changed in statute, the Government has now accepted that the Commons is opposed to leaving the EU without an agreement. Later today, MPs will debate a new motion on delaying Brexit, for which there seems to be a majority. With the path to a No Deal Brexit disappearing, Eurosceptic critics of the deal should look again at Theresa May’s deal and, in particular, at the reassurances and clarifications she obtained at Strasbourg on Monday night.

The package agreed at Strasbourg came just hours before the second meaningful vote on Tuesday. As Paul Goodman observed, MPs were being bounced, and needed a “day or two’s deliberation” to weigh up the effect of any legal changes. Jacob Rees Mogg sagely suggested in advance of the vote that delay would have been sensible because “if people feel that they have been bounced, hurried and harried, their natural instinct is not necessarily to cave in, but to stiffen their resolve”. The Government, however, pressed ahead to another defeat (although they did persuade various influential backbenchers to back the deal including, most notably, David Davis).

The fate of the Prime Minister’s deal seemed sealed when the Attorney General’s legal advice was published. To Geoffrey Cox’s credit, he refused to bend his advice to political expediency. But his stark final paragraph kicked away the ladder that some erstwhile critics of May’s deal were halfway through climbing down. And, crucially, his line that a legal risk remained unchanged – “the United Kingdom would have…no internationally lawful means of exiting the Protocol’s arrangements, save by agreement” – distracted attention from a far more significant change outlined in his advice.

Eurosceptic critics of the deal have long been rightly concerned that the UK could be ‘trapped’ in the backstop if the European Union refused to negotiate in good faith. These fears were exemplified by a threat which Emmanuel Macron made in November – that the EU would use the backstop as a “lever” to extract concessions from the UK. He strongly implied that the UK would be forced to “remain for the long term in a customs union” unless it conceded on the future relationship, fishing rights and so on. This tallied with reported comments made by Sabine Weyand.

The changes agreed at Strasbourg on Monday night addressed that important concern. As the Attorney General himself noted in Paragraph 17 of his legal advice, the Strasbourg package of changes “reduce the risk that the United Kingdom could be indefinitely and involuntarily detained within the Protocol’s provisions at least in so far as that situation had been brought about by the bad faith or want of best endeavours of the EU.

The risk that remains unchanged as per the concluding Paragraph 19 of his legal advice is a separate legal concern – that is, that the UK is unable to put forward any workable solutions to the Irish border. In that case, the backstop would remain binding under international law, unless fundamental circumstances changed.

But Eurosceptic critics of the deal are rightly convinced that a combination of technology, alignment, cooperation and facilitation can resolve the Irish border issue, as long as the EU does not arbitrarily refuse to engage with whatever the UK puts forward. In addition, the final paragraph of Cox’s advice notes that were the UK trapped in the backstop and there to be a “fundamental change of circumstances”, the UK could suspend or even exit the backstop under the Vienna Convention on the Law of Treaties.

A new legal opinion published by Guglielmo Verdirame QC – a professor of International Law at King’s College, London – sets out a number of important points which “may have been lost or not fully appreciated in the noise of interventions and commentary of the last hours”. Together with Professor Richard Ekins and Sir Stephen Laws, Verdirame had already written, in a paper published by Policy Exchange back in December, that, even before Monday’s changes, the UK would have had arguments in the event of the backstop becoming a trap. His opinion now reinforces the interpretation that the Strasbourg package has further improved the UK’s legal position. Crucially, Verdirame argues that:

“the risk of the backstop being used as leveraging for the next phase of the negotiations to lock the EU into a backstop-like arrangement indefinitely has receded significantly. In particular, it would be clearly incompatible with its obligations under the Withdrawal Agreement, [backstop] Protocol, and Joint Instrument , for the EU to adopt a negotiating stance that boils down to the position that only ‘backstop 2.0’ can replace the current backstop.

For similar reasons, it would be inconsistent with its obligations for the EU to adopt a stance that reflects the position attributed to President Macron, i.e. that the UK would have to pay a price (e.g. in terms of access to fisheries) to leave the backstop. The UK should indicate, in no uncertain terms, that it would regard an approach by the EU to negotiations on such basis, or on the basis of the leaked Weyand memorandum from last November, as incompatible with the EU’s obligations under the WA [Withdrawal Agreement] /Protocol and, more so, as clarified and amplified in the Joint Instrument .”

Moreover, contrary to views that circulated on Tuesday, Verdirame explains, it is incorrect to say that a dispute about whether the EU has acted in “good faith” in seeking to replace the backstop would end up being determined by the European Court of Justice on behalf of the arbitration panel.

There has, he suggests, been a great deal of confusion about what the concept of “good faith” means in this context – perhaps due again to the limited time that people had to reflect on these documents and to predictable attempts by those interested in stopping Brexit in creating a “nothing has changed” narrative.

To be clear: to win a hypothetical case against the EU for breach of the “best endeavours in good faith” obligation, and of the separate obligation to implement the Withdrawal Agreement including the backstop in “good faith”, the UK would not have to demonstrate “bad faith” on the part of the EU in the English law sense of dishonesty, fraud or deceit.

In one of the cases cited by Verdirame, the most important international judicial body, the International Court of Justice, said: “The principle of good faith obliges the Parties to apply it [the Treaty] in a reasonable way and in such a manner that its purpose can be realised.” This means the EU could not merely sit back, wait for UK proposals on avoiding the backstop and then reject them all. It would have to be not only reasonable in considering UK proposals, but also proactive in advancing its own solutions, which could not amount to – as Verdirame puts it – just “backstop 2.0”, that is something which for all intents and purposes replicates the backstop. So as a result of the Strasbourg package, the EU could not simply insist that it could only replace the backstop with something that looks like a backstop, swims like a backstop and quacks like a backstop – i.e. a customs union.

Critics of the Prime Minister’s deal understandably felt they had far too little time to consider the legal implications of the changes secured at Strasbourg. Those changes were less than many MPs had hoped to see. The EU has refused to move to a proper time limit or a clear unilateral exit mechanism. But just because Brussels wouldn’t move all the way, oesn’t mean that what they offered wasn’t significant. Key EU member states strongly resisted the Commission’s move to make the commitments offered in a letter exchange back in January fully legally-binding. They did so because they knew that they strengthened the UK position.

Amidst the maelstrom of Tuesday’s Brexit drama in Westminster, it was easy to miss the reaction of the Irish opposition. Fianna Fail’s Brexit spokesperson, Lisa Chambers, noted that there had been changes and that “we have come a long way” from a “bullet-proof, rock-solid, cast-iron backstop”.

Where we have landed is with a package of legally-binding guarantees agreed at Strasbourg which substantially shift the UK’s position regarding the backstop. Neither the EU or the UK side now have quite what they want – both positions are sub-optimal.  But many of the legal risks for the UK have been substantially reduced, although not entirely eliminated. At a certain point in any negotiation or any decision the question must focus on the politics, not just the law. We are now there.