The Northern Ireland Protocol contains the means of its own suspension: Article 16.  This refers to “safeguard measures” which can unilaterally be taken by either the UK or the EU if “the application of this Protocol leads to serious economic, societal or environmental difficulties that are liable to persist, or to diversion of trade”.

“Such safeguard measures shall be restricted with regard to their scope and duration to what is strictly necessary in order to remedy the situation,” it continues – which leaves open the question of what that duration and scope might be.

The EU itself will presumably need no reminder of the terms of Article 16 – because it invoked them itself in January to prevent vaccines made in the Union being exported from Northern Ireland to Great Britain.

Is the Protocol leading to “serious economic, societal or environmental difficulties”?  We will pass over the last but not the first – let alone the one in the middle.

On economic difficulties, there have been frequent and continuing reports of food shortages in Northern Ireland’s supermarkets: more or less at random, we link to accounts from January, April and yesterday.

On societal ones, successive opinion polls have confirmed what loyalist marches, and placards demanding “no sea border”, suggested – namely, that support and opposition to the Protocol are dividing along political lines.

One cannot introduce to a settlement built on cross-community consent a measure that 47 per cent of those polled believe is appropriate for Northern Ireland…and 47 per cent believe is not appropriate.

Let alone one whose operation to date sometimes leaves shelves empty in the province’s shops – which touches on the everyday lives of those of all political and religious convictions and none.

The Government thus has grounds to invoke Article 16 that have nothing to do with Boris Johnson signing the Protocol because Theresa May had left him no practicable alternative; or because the Government underestimated the Protocol’s effects.

Nor do Ministers need to imply that the Protocol is incompatible with Part 1 (iii) of the section of the Belfast Agreement, which says that “it would be wrong to make any change in the status of Northern Ireland save with the consent of a majority of its people”.

Nor to cite the references to “Northern Ireland’s integral place in the United Kingdom’s internal market” in both the Protocol’s preamble and Article 5.

Nor do they have publicly to draw the obvious conclusion from the Protocol’s references to the Agreement – namely that, as Roderick Crawford has written on this site, the first isn’t fully compatible with the second.

Some Conservatives will agree with all these supplementary arguments and others with only some of them.  This site confesses to be unimpressed by those based on not appreciating the Protocol’s effects, or it having effectively been signed under duress.

For governments ultimately have a choice in these matters – and the fact of the matter is that Brexiteering Tory backbenchers were ultimately prepared to gamble on a settlement that contained a different regime for Northern Ireland.

Nonetheless, the EU is not obliged by the Protocol to seek the strict and rigid policing of the Irish Sea border – as though the flow of goods east-west to Northern Ireland constitutes an existential threat to the integrity of the internal market.

The nub of the matter is that the EU is angling for a UK alignment on food safety standards, and the UK has been holding out for an equivalence agreement.

The main gripe of the Government is that the EU is once again seeking to manoeuvre the UK into the orbit of its institutional order and the European Court.  Obviously, this is inconsistent with “taking back control”.

The chief complaint of the former is that the Government has consistently dragged its feet on putting the infrastructure and staff in place to ensure that the Protocol will operate properly.

We suspect that the EU has a point here, but that Ministers have a larger one – namely, that they’ve come to believe that there’s no point in trying to get the Protocol to work, because lack of Unionist consent renders it unworkable, at least in its present form.

So it is that the Government has been unilaterally extending “grace periods” to keep the flow of food going to Northern Ireland; and has now taken the least inflammatory of the three resistant options open to it.

It could have announced that it is resiling from the Protocol, thereby putting itself on the wrong side of international law.  Or it could have sought to proceed with Article 16 immediately.

Instead, Lord Frost said yesterday, “this is not the right moment” to invoke the Article – even thought “the circumstances exist” that would justify such a move.

In short, the Government’s position is that the Protocol must be revisited, and the EU’s response is that it won’t be: no surprises there.  The question that follows, as so often in these affairs, is whether there is room for a diplomatic fudge.

As Stephen Booth pointed out recently on this site, the latter moved recently on the movement of medicines into the Northern Ireland market, so flexibility clearly isn’t impossible.

Until yesterday, the EU and UK had agreed to put aside their differences until September, having agreed a three-month extension to a grace period allowing chilled meats to continue to move from Britain into Northern Ireland.

By making it formally clear that the Government regards the Protocol as unworkable, Johnson, Frost and Brandon Lewis have both followed the logic of their position and taken a step into the unknown – especially in terms of the knock-on effect in Northern Ireland.

At any rate, the EU and the UK, as co-owners of the Withdrawal Agreement and the Protocol, have a co-responsibility to ensure that the Belfast Agreement continues to work.

And it doesn’t follow that because it did so pre-Brexit, when Great Britain as well as Northern Ireland was within the internal market, it cannot now do so post-Brexit. What’s needed is a dollop of what brought the Agreement into existence in the first place: a good old-fashioned fudge.  Which won’t happen if the EU insists on policing its Irish frontier against threats that don’t exist.