Perhaps face masks will live on in the UK on not as a lingering safeguard against pandemics, but as an artefact of Ulster loyalism.  For over the weekend, anti-Covid coverings mingled with balaclavas at an anti-sea border protest in Portadown.

The marching, the lambeg drums, the flutes and the anonymous menace of the covered faces were sending a message – from one of Northern Ireland’s flashpoint locations during the run-up to the marching season.

Which is: the Northern Ireland Protocol is unacceptable, at least as the EU sees it, to a swathe of not only loyalist but wider unionist opinion. The point was made by the attendance of the local DUP MP, Carla Lockhart.  And by that of the new UUP leader, Doug Beattie.

You may respond by saying that loyalist paramilitaries, who were clearly the moving force behind the event, should not be allowed to dictate the terms of democratic politics.

Indeed – but that pass was sold a very long time ago.  The Combined Loyalist Command was one of the backers of the Belfast Agreement, under the terms of which a troubled peace was brought to Northern Ireland.

Hence the significance of its recent declaration that the Protocol undermines the basis on which loyalist groups “agreed their 1994 ceasefire and subsequent support for the…agreement”.

Another supporter was the IRA, through the medium of Sinn Fein.  No less magisterial a figure than Chris Patten warned, during Theresa May’s premiership, that a hard land border on the island of Ireland risked becoming “a focus for violence”.

A hard sea border between Britain and Northern Ireland is evidently such a risk too – so what’s good for the republican goose is also good for the loyalist gander, as Lord Patten would presumably concede.

Perhaps the Protocol is itself a breach of the Agreement, and of the consent principle which underpins it.  After all, the Agreement declares 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”.

Some say so; others say not.  Some, too, argue that Brexit itself was a change in status (though it was one, of course, also undertaken by England, Scotland and Wales.).

But behind the lawyerly text of the Agreement are the grim realities of Northern Ireland’s politics, one of which is that any settlement must be broadly acceptable to unionists and nationalists alike.

This truth is actually written into the Protocol itself, which commits its signatories to “maintain the necessary conditions for continued NorthSouth cooperation, to avoid a hard border and to protect the 1998 Agreement in all its dimensions” [our italics].

So by threatening sanctions with the UK over the Protocol’s implementation, the EU is, to borrow another phrase from Lord Patten’s intervention three years ago, “blundering into the politics of Northern Ireland…with a can of petrol and a box of matches in the other hand”.

Essentially, it is placing a theoretical threat to the security of its internal market, which preoccupies France and the Commission, over the peace in Northern Ireland which it claims to have helped create, and to which the Protocol that it signed is committed.

And if a harder border on either the island of Ireland itself or in the Irish Sea menaces the Agreement, it follows that the only way of squaring it with Brexit is, in effect, scarcely to have one at all.

In other words, checks should be carried out with the lightest touch possible.  The Protocol requires neither treating goods intended for Northern Ireland’s supermarkets as a threat to the Single Market; nor regulatory alignment to ensure that the possibility never arises.

Above all, it’s a bit rich of the EU to bang on about honouring the Protocol when it rode roughshod over it as recently as January – invoking Article 16, a safeguarding clause, to stop vaccines going to Northern Ireland for fear that they would end up in Great Britain.

But rather than segue into a wider sketch of the EU’s immobility and hesitancy, let’s stick with the future of the Protocol.  The prospects for Northern Ireland are ominous.

The Government has three options.  The first is to agree to a hard sea border, and risk peace in Northern Ireland collapsing – one amplified by the pressure from angry unionists on a flailing DUP, as both harder line and softer ground voters look elsewhere.

The possibility of a Sinn Fein First Minister after the next Stormont elections will do nothing to ease tensions during the coming months.  The second option is sticking with the Protocol, but continuing to extend grace periods.  The third is to invoke Article 16 itself.

That last option would convulse the UK-EU relationship, such as it is, and bring a swift referral of the matter to the European Court.  The middle one would be less noisy, but end up in the same place.  (Indeed, legal action has already followed the present grace periods.)

We’re told that the Government’s nightmare is not so much a European Court ruling, but our own courts taking the same view.  Which would imply Boris Johnson bringing forward legislation to ensure that the Protocol brings with it no obligations under domestic law.

Lord Frost might well be up for this.  After all, he has said that the Protocol is unsustainable in its current form.  But this site is not at all sure about the rest of the Cabinet.

This helps to explain the wave of negative briefing against Frost from the EU end.  Isolate the last senior Vote Leave stalwart left standing, now that Dominic Cummings has gone, and Johnson might concede that harder sea border.  Who knows?

Tough, say some.  That’s what he signed up to when he clinched a deal in the first place.  We would answer that he isn’t obliged to agree to the hardest one possible.

But even if we’re mistaken, it’s simply wrong to hurl “you broke it, you own it” at the Prime Minister.  He may have broken it but – and we can’t point this our often enough – he doesn’t own it.  He co-owns it.

For while Northern Ireland remains an integral part of the UK, the Withdrawal Agreement, which places Northern Ireland in the Single Market for manufactures, is co-owned by both our own Government and the EU.

Just as the Belfast Agreement is co-owned by our Government and Ireland’s.  So the EU now has a formal responsibility for Northern Ireland that it didn’t have before.

Sure, it can go to the European Court, or start a trade war, or both.  And it could mobilise Joe Biden, or try to, if Johnson moves to bring in new legislation.

But if it does so, can it spare us, please, the pieties about protecting the Belfast Agreement and Northern Ireland’s fragile peace.  For the EU, its pressing problems today clearly come second to distant ones for the internal market – insofar as they exist at all.