One reading of the deal signed last week by UK and EU negotiators is that it guarantees full regulatory alignment between Northern Ireland and Ireland if the land border issue is not resolved during the talks to come.  (Such alignment is in effect the same as no regulatory divergence, according to Gisela Stuart of Vote Leave on this site).  It follows from this logic that, since the Government and the DUP agree that Northern Ireland must not be treated differently from Great Britain, the whole of the United Kingdom would be signed up to such alignment.  And it follows again that, since this is the case, we would effectively be bound to the Single Market and Customs Union – at least in matters that flow from Strand Two of the Belfast Agreement, such as agriculture.  This would make it impossible to agree the unrestricted non-EU free trade deals that are an instrinic part of a coherent Brexit.  The main part of Liam Fox’s job would become redundant.  This view is put with particular force by some Irish commentators and Remain campaigners.

Such a take on the deal has the potential to bring down Theresa May and her Government.  Roughly half the Conservative Parliamentary Party voted Leave.  Much of it would find such an interpretation, duly implemeted, very hard to bear indeed.  The pro-Brexit MPs concerned would be torn between, on the one hand, their yearning to break free of the Customs Union and Single Market and, on the other, their fear of anything likely to bring Jeremy Corbyn nearer power.  So May and her team have a pressing need to reject this view.

They find refuge in the words of the preamble to the deal, repeated in Article Five, that under the caveat that nothing is agreed until everything is agreed [our italics], the joint commitments set out below in this joint report shall be reflected in the Withdrawal Agreement in full detail”.  This section of the deal also says that the commitments are “without prejudice to discussions on the framework of the future relationship”, which would also imply possible departure in the talks to come from the deal’s text.

(Furthermore, they argue that the words “full regulatory alignment” do not appear in it.  This is correct.  The form of words used is “full alignment”, and the gloss that Ministers are putting on them – such as David Davis yesterday, for example – is that they refer to the mutual recognition of standards, which obviously does not imply capture by Single Markets and Customs Union rules.  Such an outcome would leave the Government fully free to strike those trade deals.)

Not so fast, say Irish Ministers, Article 46 of the deal specifically says that commitments made as part of the deal “must be upheld in all circumstances, irrespective of the nature of any future agreement between the European Union and United Kingdom”.  The only sensible conclusion to draw is that Article Five, which says that nothing is yet agreed, contradicts Article 46, which says that agreements made to date must be upheld.  Welcome to what has been called Schrodinger’s Brexit.

May, Leo Varadkar, Jean-Claude Juncker, Donald Tusk – the whole lot of them – are thus struggling in a net of their own devising.  And given the disagreement between London and Dublin over the deal’s meaning, one cannot presume that the European Council will confirm later this week that trade talks can start.  Getting to the brink of them was a diplomatic win for the Prime Minister last week. Falling back again would return her to the perils that threatened her between last Monday and Friday.

May is very conscious of the importance of keeping Boris Johnson and Michael Gove in her Cabinet and onside with the deal.  This is why Gove was licensed to write his Daily Telegraph article of Saturday which repeated the “nothing is agreed until everything is agreed” mantra.  Davis made the same argument yesterday.  And the Prime Minister herself has apparently repeated it in a letter to Conservative MPs, which also says that “full alignment” means “sharing the same policy goals even if we achieve them by different means”.  The Government seems to be on firm ground here.  Those two words would not have been written into the deal’s text without EU negotiators and Irish civil servants recognising their ambiguity, and letting them pass.  The Government is less well placed on the standing of the deal itself.  This is less because its text is decisive either way than because common sense suggests it.  It cannot agree a text and then query its status without raising questions about whether Britain can be relied upon to honour commitments it has entered into.