We are so used to seeing Northern Ireland politics as a zero-sum game that it’s hard to acknowledge a political deal which might benefit everyone.

Jon Tonge is a Professor of Politics at the University of Liverpool. He is the author of The Democratic Unionist Party: From Protest to Power. Oxford: Oxford University Press.

We are so used to seeing Northern Ireland politics as a zero-sum game that it’s hard to acknowledge a political deal which might benefit everyone. That might partially explain why the endorsement of Friday’s Phase 1 Brexit agreement.

Amid the ambiguity and verbiage what was tentatively and sensibly proposed was a Common Trade Area between the UK and Ireland, to match the longstanding Common Travel Area. It gave the Irish government what it wanted – no hard border and unfettered cross-border trade; ditto the UK government. The DUP’s primary concern was addressed: departure from the EU on the same terms as the rest of the UK.

Laughably, the agreement also states no new regulatory barriers can develop between Northern Ireland and the UK unless the Northern Ireland executive and assembly agree. So, all that’s needed for then is for the Executive to be reconstituted, the Assembly restored and every DUP and UUP MLA to be stuck in a snowdrift en route to the Stormont vote facilitating these new internal market barriers.

The agreement states that the UK should resolve the border via its own, broad-based EU trading relationship. If this is not possible, there should be specific solutions for Ireland. If both these options fail, there will be regulatory alignment. Given that this default solution is the best one, provided of course that there is also tariff-free trade across the border on the island, why propose solutions when the default looks best? Just keep the UK’s regulatory rules the same as those of Ireland/the EU. No-one wants divergence between Northern Ireland and Ireland’s key sectors, such as agriculture, anyway.

It’s the proposals for trading with the 26 other EU member states that the UK now needs to worry about. The obvious hope is that the UK government realises that, regulatory convergence and tariff-free trade is, well, actually, quite a decent idea. So, son or daughter of the Single Market and Customs Union emerges as the overall deal – but, unlike other Customs deals, the UK remains entitled to conduct all those fantastic free trade deals, for those quality British goods, that the rest of world is queuing up to sign….

Quite why it was so difficult to fathom that a UK-Ireland border deal might fly, whereas a special status Northern Ireland-Irish Republic one wouldn’t, is a mystery. It’s hardly as if the DUP Ten have been quiet or invisible.

It’s actually the DUP 11 – and no, I don’t mean adding Arlene the Leader. The most fervent Brexiteer in the DUP, often overlooked despite her significant input to policy, is the Party’s MEP, Diane Dodds. Her Euroscepticism has been exacerbated by her stint in Brussels and contributed to the DUP’s pro-Leave undiluted stance – which, briefly, during Cameron’s re-negotiation with Brussels, looked as if it just might be tempered.

Dodds (Diane) also knows a lot more about the EU than most in her Party. That might seem a case of damning with the faintest of praise, but, trust me, she is more clued up than many realise. I got a taste of this as I headed to Brussels to give evidence on Brexit options for Northern Ireland to the European Parliament’s Constitutional Affairs Committee in late October. I was summoned to Dodds’s office in advance and she trawled through every powerpoint slide I was giving that afternoon – challenging several of the possibilities with a fair bit of clarity and evidence. That’s not to say we agreed on a lot of the details – but the precise limits to where the DUP would be pushed voluntarily were clear enough.

Those limits did not preclude strong North-South trade. After all, Dodds could hardly disobey the leader still worried, expressed only a year earlier in a letter to the Prime Minister, that Northern Ireland’s agri-food sector was ‘uniquely vulnerable both to the loss of EU funding, and to potential tariff and non-tariff barriers to trade’. The DUP is many things, but it’s a free trade Party and will not oppose sectoral alignment facilitating that trade where it’s useful. This of course makes the Party’s fury, which delayed Friday’s agreement, that bit odder. The DUP opposed full regulatory alignment. But alignment in sectors where the North and South of the island aren’t doing cross-border business anyway hardly matters. Onwards to the next phrases in the struggle.