There are two specific commitments at the heart of the Agreement Between The Conservative And Unionist Party And The Democratic Unionist Party On Support For The Government In Parliament, jointly signed on June 26, 2017.
''The DUP agrees to support the Government on all motions of confidence; and on the Queen's speech; the Budget; finance bills; money bills; supply and appropriation legislation and Estimates.''
''As set out in its General Election manifesto the Conservative Party will never be neutral in expressing its support for the Union. As the UK Government we believe that Northern Ireland's future is best secured within a stronger United Kingdom. We will always uphold the consent principle and the democratic wishes of the people of Northern Ireland. The Conservative Party will never countenance any constitutional arrangements that are incompatible with the consent principle.''
In the last few days the DUP has clearly and very deliberately breached its commitment by refusing to back the government on a number of votes. That's because they claim that Mrs May has breached her commitment by seeming to countenance a constitutional arrangement which is 'incompatible with the consent principle.' May, of course, insists that since the consent principle is - and will continue to be - based on a majority in Northern Ireland voting to leave the UK, she has breached nothing. And, in the very strictest sense, she is right. Irrespective of what happens re the final Brexit deal-or no deal-the Union between NI and GB is still dependent on the will of the people here.
Where the PM is on much shakier ground, though, is the fact that the terms of her Withdrawal Agreement (and in one sense this is her agreement) could require Northern Ireland to be treated differently, very differently, from the rest of the United Kingdom. I accept the argument of those who say that Northern Ireland is already different in many ways (particularly on issues like abortion and same-sex-marriage); but those differences - which I oppose, by the way - are not constitutional differences. But Northern Ireland having a future relationship with the EU which is not the same as the relationship between GB and the EU does raise existential and constitutional problems for unionism.
Imagine the 1972 White Paper on Northern Ireland without the concept of the 'Irish dimension' included. Imagine the Anglo-Irish Agreement and Good Friday Agreement without the specific provisions for the recognition and protection of nationalist aspirations and identity. The DUP - and unionism more broadly - fear that the Withdrawal Agreement and an eventual final deal don't embrace a Northern Ireland unionist 'dimension, let alone recognition and protection of their aspirations and identity. In other words, they fear that the 'consent principle' means nothing against a background in which NI, albeit incrementally, becomes less unionist, less linked to GB.
I've argued many times in this column that there was likely to be a 'moment of truth' collision between Theresa May's 'national interest' and the DUP's 'specific Ulster unionist interest.' That's where we stand now. I think the DUP had hoped that May might have been brought to heel by her own rebels or a vote of no confidence, but that doesn't seem to be happening; meaning that the only tactic they have is the non-voting one. They could walk away from the confidence and supply arrangement, but that could lead them into pyrrhic victory territory.
Having clout over the government is important for them: if nothing else it makes life very difficult for both the prime minister and secretary of state when it comes to room for manoeuvre in the NI politics/talks process. That clout also played well with the DUP's grassroots, who liked having a chain around the prime minister's neck. But today it looks like that 'clout' has delivered what one DUP MLA described to me a few days ago as: "The same old betrayal we're used to."
Boris Johnson will be a guest at the DUP's annual conference tomorrow. I'm not sure what message the DUP is trying to send. It's not overegging it to say that he is May's mortal enemy and nor is it understating it to say that he is very unlikely to replace her. So I'm presuming that he will take the opportunity to put the boot into her, assured of an adoring audience and a thunderous ovation.
Yet not one DUP member will ask him how come he has failed to stop her, or overthrow her; or, more pertinently, why he has failed to persuade enough of his colleagues to sign letters of no confidence in her.
This is new and very difficult territory for the DUP: a new woe in a veritable ocean of woes for them. A photo-opportunity with Boris won't be enough to save Arlene's bacon.
