There are three main battleground obstacles to a Conservative majority next year – the disunity of the Right (with UKIP drawing more votes from the Tories than from Labour), the unity of the Left (with left-wing Liberal Democrat voters defecting to Ed Miliband’s party), and the distribution of the vote (which favours Labour).  There is also a longer-term fourth factor: the growth in the ethnic minority vote, which goes mostly to Labour.  Rishi Sunak of Policy Exchange wrote on this site earlier this week that by 2050 ethnic minority members may make up as big a proportion of voters as one in three.

All this being so, the best David Cameron may be able to do is to lead his party back to the Commons next May as the largest one – in a result not unlike that of 2010 (assuming a No vote in Scotland).  This is certainly possible, arguably even likely: on this site today, Kevin Toolis, himself a man of the Left, eviscerates Labour’s class war Euro-election broadcast of earlier this week.  It was, he writes, “awesomely bad, a grotesque dog of a film, superlatively and wondrously inept, politically unhinged and I suspect to most members of the general public entirely incomprehensible. A turkey of Oscar-like proportions”.  All I can add as a footnote is the obvious: its attack on Clegg shoved the narrowness of Ed Miliband’s electoral ambitions under a spotlight.

Were that 2010-style result to happen, two main options are canvassed – a second coalition, or a minority government.  The Guardian today floats a third: a confidence and supply arrangement with Northern Ireland’s Democratic Unionists.  The province’s MPs have a history of importance in Parliaments in which the government of the day has a small majority, or none at all.  The Ulster Unionists helped to prop up John Major during the 1990s and Jim Callaghan during the 1970s.  The DUP is not the same party, but there is none the less a lesson from history here – namely, that what determines Unionist votes in the lobbies is less ideology than favours, electoral or financial.  It must be added that in this they are scarcely unique.

Downing Street is certainly eyeing the DUP with interest.  A straw in the wind has blown across this site in the form of a piece by Mel Stride on a possible deal.  “For Conservatives, an alliance of sorts could offer those vital additional seats that might make all the difference to our prospects for continuing to govern,” he wrote with disarming frankness. Stride isn’t any old (or young) Tory backbencher.  As PPS to John Hayes, himself PPS to the Prime Minister, he is in and out of Number 10 more than a bit, and knows the score.  Is such an arrangement possible? Clearly, yes.  Would it last? Not necessarily: most of the Ulster Unionists voted to bring Callaghan down at the end, including Enoch Powell.

What effect would it have on Northern Ireland?  The logic of the Sinn Fein/IRA strategy since at least the 1990s has been to drop the armalite and embrace the ballot box.  But what can certainly be said is that a deal between the Tories and a party which – let’s face it – represents not only Unionist but Protestant interests in the province would do nothing to make its uneasy peace more durable.  Gerry Adams’s arrest and release over the murder of Jean McConville was a reminder that Northern Ireland’s bloody past is helping to shape its present.