There is a core case against doing a deal with the Democratic Unionists.  It is that the balance of numbers in the Commons leans against them coming to terms with Labour, and that they won’t do so anyway while Jeremy Corbyn and John McDonnell are in charge of it.  So Theresa May can side-step all the awkwardnesses that would accompany a confidence-and-supply arrangement with the DUP by not agreeing one at all.  It will vote with the Conservatives in any event.

This argument is a bit too clever-clever by half.  If the Conservatives can’t come to forma terms with the DUP, they enter minority government pure and simple.  And while this may be sustainable all the way through to 2022 (though we very much doubt it, fixed-terms act or not), there is a difference between minority government with support elsewhere in the Commons and minority government without it.

Very crudely, the sliver of extra votes that would come with a confidence-and-supply deal, or something as like it as to make no difference, is likely to make all the difference between winning crucial votes and losing them.  That matters to the coherence and workability of the Government.  It has an impact on how May and her ministers are seen abroad – no small matter given the Brexit negotiation.  It helps to reassure the markets. DUP MPs turning up to vote with the Conservatives, rather than flying back early to Northern Ireland on a Thursday or just not being there at all, makes it just a bit more likely that May can deliver a programme.

With their bowler hats and Union flags and drums and funny walks, and roots in religious sectarianism, the DUP might have been invented to get up the noses of London’s media liberals.  But there are plenty of religious bigots in Northern Ireland, and not all of them are Protestant, by any means.  The DUP is under assault for its conservative position on abortion, but this is the same in essence as the Catholic SDLP’s.  Left-wing hypocrisy on this point is nauseating.  In any event, Northern Ireland is a more socially conservative place than Greater London, the values of its people will find an echo in England’s provinces, and many Conservative Party members are themselves social conservatives.  (Hint: the clue is in the Party’s name.)

Furthermore, the DUP has moved on from its origins in Ian Paisley’s firebrand preaching.  It occupies much the same space in Northern Ireland’s politics as the Ulster Unionists did until very recently.  (Yes, that’s the same Ulster Unionists that John Major came to an understanding with during the 1990s, a point that exposes his grandstanding yesterday about May doing much the same with the DUP 25 years on).  It gets some Catholic votes.  Its leaders are a known quantity to Dublin’s political classes.  Above all, this Union-flag bedecked monster has recently been squatting in coalition with Sinn Fein, whose very name can excite parts of Labour’s Left to the point of bedwetting.  If the DUP is so offensive to civilisation, why did Gordon Brown seek a deal with it in 2010?

None the less, the case for being wary of a DUP arrangement has a curious persistence, even after each part of it has been dismissed.  It lingers in the air like a stubborn smell.  The message of Jeffrey Dudgeon’s recent piece on this site – that the DUP is flexible about gay sex, if that is quite the right way of putting it – may not get through to younger voters, with whom the Conservative Party is having a bit of a hard time.  And while the claim that the Tories are neutral about Northern Ireland is wrong – we back the union – a DUP arrangement would raise questions. It is not inconsistent with the terms of the Belfast Agreement.  But it would make it harder for the Secretary of State to be seen as an honest broker in Ulster were he formally aligned with one of its parties at Westminster.

Then there is policy.  The DUP is less a free market party than an economically populist one.  The core of its Northern Ireland Programme – drawn up before 2015 in anticipation of a hung Parliament – is, not to put too fine a point on it, screwing money out of the English taxpayer. “Northern Ireland business to be in a position to get a fair share of government contracts…ensure that Northern Ireland maintains its 100% regional aid status…Northern Ireland prominently incorporated into UK branding”: you get the picture.  None of this pork-barrelling is remotely discreditable – which MP does not seek a bigger slice of the cake for his constituents? – but England’s Just About Managing Classes may get Just A Bit Cross.

Some party members will be relieved that the DUP’s populism extends to support for the pension triple lock and the winter fuel allowance – although they may raise an eyebrow at its 2015 support for removing “the bedroom tax at a national level”.  And those Brexiteers who feel an affinity for the DUP, or warm to its support for Brexit, may want to pause for a moment.  That backing does not prevent it from taking the same position on the border as the Irish Government: it would prefer no border controls at all, as now, to the “frictionless” ones that May has floated.  That could be read to mean staying in the Customs Union, for which a strengthened Chancellor is again pushing.

All this will no doubt be bartered to and fro.  The DUP is making a big show of not leaping into bed with the Prime Minister.  The requirements of politics compel it to play hard to get, even though there is no other suitor to hand.  Although some Conservative MPs are uneasy, some deal of some sort will probably be struck, and May will have an orange figleaf with which to shield her exposed position.

ConservativeHome is not quite sure where an arrangement with the DUP would leave Party members’ longing for a non-green, non-orange, red-white-and-blue-only non-sectarian force in Northern Ireland: i.e, for the Party itself to build up its position in the province.  But such yearnings must be postponed.  Yes, a deal with the DUP may have unexpected consequences in the province and elsewhere, but May has little alternative but to seize Nigel Dodds by the hand and take him for a bop on the dance floor.  Mind where you tread.