One would scarcely know it from Donald Tusk’s response to Boris Johnson’s letter.  But the EU itself is obliged to “work at speed” to ensure that alternative arrangements to the Northern Ireland backstop are found by January 2021 – that’s to say, in less than 18 months.  There is even to be a “dedicated track…embedded in the overall negotiation structure”.  This is to guarantee that no effort is spared – with regular reviews “at each subsequent high level conference”.  All this is set out in the joint statement agreed by the EU and UK shortly before the second meaningful vote on the Withdrawal Agreement.

The European Council President made no reference to this pledge whatsoever, dismissing the Prime Minister’s letter as “not proposing realistic alternatives” – rather than, as the EU is committed to do, proposing positively to seek alternative arrangements, instead of simply and negatively dismissing any ideas put forward.

In a certain sense, however, one cannot blame Tusk.  The “backstop solution in the Protocol on Northern Ireland”, as he called it, works for the EU and for Ireland, for two main reasons.  First, it is the most straightforward solution to managing the complexities of the UK-Ireland land border.  Second, the EU is convinced that London will have to concede it sooner rather than later.  Johnson’s Government has no real working majority.  The Commons is collectively anti-No Deal.  So either Johnson will give way on the backstop, and No Deal won’t happen, or he won’t, and it might – in which case the UK will crack under the consequent pressure.

Or so the EU seems to think, which calls into question its commitment to the joint statement.  It complains that the Prime Minister is asking for the UK to be taken on trust over the Northern Ireland border.  He might reasonably reply that the EU is itself asking to be taken on trust over its promise to seek alternative arrangements quickly.

However, this mutual blame game is beside a central political point.  The EU and its Remain backers here talk as though the UK is committed to the Withdrawal Agreement.  However, that is not the way our system works.  Under its terms, the Executive cannot simply agree whatever it likes.  If Ministers sign an agreement, MPs must approve it for it to be effected – or so it has been with a long line of treaties with the EU, from Maastricht through to Lisbon.  The Withdrawal Agreement hasn’t been put to the Commons in the form of a Bill.  Indeed, MPs have rejected it in principle no fewer than three times.

This is the very same point that Remainers make about Brexit as a whole: that, ultimately, it is Parliament that decides.  But what is sauce for the goose is also sauce for the gander: it is also Parliament that decides the fate of Withdrawal Agreement, including the Northern Ireland backstop.

So while the EU might wish the democratic facts to be otherwise, they are as they are.  The plain fact is that this Commons will not pass the Withdrawal Agreement.  It is a dead parrot.  And, lest it be forgotten, the very same MPs who now criticise Johnson over his position on the backstop actually voted against it themselves: Vince Cable and Ian Blackford; Keir Starmer and Jo Swinson; Caroline Lucas and Yvette Cooper – all these, and more, voted against the Withdrawal Agreement and the backstop it contained.  Johnson’s own vote for it, third time round, was part of its last Parliamentary gasp.

Indeed, the only majority MPs have shown for any recent Brexit proposal was for Graham Brady’s amendment, which said that the Northern Ireland backstop should be renegotiated altogether: exactly the Prime Minister’s position. Almost the entire Conservative Parliamentary Party voted for it – even Ken Clarke.

As we suggest above, the EU and the Irish Government can scarcely be blamed for settling on a backstop for the UK-Ireland land border.  Nor is it surprising that the latter presents it, especially in America, as necessary for the upholding of the Belfast Agreement.  Fault lies, rather, with Theresa May’s Government for accepting this reading of it, and the pro-Union family more broadly for not contesting it, at least until very late.  DexEU was not across Northern Ireland.  Downing Street made no real use of the one Tory official in the Northern Ireland Office who was – Jonathan Caine, the former Special Adviser.

The DUP have no real stake in the Belfast Agreement, having opposed it at the time.  David Trimble – a Nobel Peace Prize winner, for goodness sake – and Paul Bew, his main adviser at the time that the Agreement was drawn up, have contested the nationalist reading of its relationship with the backstop vigorously.

None the less, they didn’t really get going until fairly late in the day.  Bew’s critiques of the green take on the interplay between the two Agreements – he argues that the Withdrawal Agreement is at odds with the consent principle of the Belfast Agreement – began to be published by Policy Exchange in January, over a year after the Joint Report on which the Withdrawal Agreement is based was signed.  This delay allowed the view that there is no alternative to the backstop to take root, as did an obsession in some pro-Brexit quarters with new technological solutions.  But, as Greg Hands writes on this site today, alternative arrangements don’t require these in order to work.

Near the core of the UK-Ireland land border row is the use of language.  “No hard border”, to the UK side, means no checkpoints, barbed wire, or new infrastucture on the border itself (which wouldn’t be practicable even were it desirable, since it would be impossible to police some 300 crossings).

But to the Irish side, it has come to mean no departure whatsoever from the status quo, together with the suggestion that the Belfast Agreement has made the island a single economic unit – hence the reference in the Joint Report to the “all-island economy”.  However, the East-West economy is a bigger presence than the North-South economy.  Northern Ireland exports £3.9 billion worth of goods and services to the Republic of Ireland, but some £11.3 billion to the rest of the UK.  And neither the Belfast Agreement nor anything else has removed the monetary, VAT, excise and security borders that divide the island of Ireland.

Which returns us to where we started.  Were the EU in earnest about alternative arrangements, it would be exploring the mix of checks away from the border, trusted trader schemes, exemptions, and all-island arrangements proposed in documents ranging from Government publications to the Alternative Arrangements Commission.  It should do – if only because some of these measures will be be needed if in the event of No Deal it decides to police its frontier.

That possibility looks remote as we write.  But, distant or near as it may be, there is no practicable alternative to alternative arrangements now, other than No Deal.  MPs have debated the Withdrawal Agreement three times, and rejected it three times.  This Commons will not accept a regulatory border in the Irish sea (and potentially a customs one, too).  It rejects dividing up the United Kingdom in such a way.  The EU may not like it, but there you go.