When it seemed just a year or so ago that Scotland might choose to regain its independence, Northern Ireland’s Unionists had plenty to say. Much of it was predictable, a matter of living up to the job description. There was, however, an undertone. It said, “What about us?”

Stormont’s politicians, Unionist politicians in particular, are keenly aware of their status within the United Kingdom’s devolved arrangements. You could say they have no choice about that. If Edinburgh or Cardiff can seem remote from London’s concerns, imagine the view – at least in times of peace – from Belfast.

Scotland’s independence argument left Unionists feeling exposed. There were cultural and historical reasons, obviously. There was an ideology to which they remain devoted. But the possible removal of the Scots from the devolution equation was depicted, in some quarters, almost as an existential matter. How would the province fare if the UK was broken apart, if the fringes of the Union unravelled?

Unionists have nowhere else to go. By definition, they have no truck with Sinn Fein’s Irish alternative. It’s the UK or bust. Or rather, as Scotland’s referendum concentrated minds, it seemed last year like a choice between a Northern Ireland boasting one of three devolved administrations within the Union, or of irrelevance for Stormont. Had the Scots voted Yes, that institution would have faced an identity crisis.

For Unionists, the Scottish crisis passed, but questions did not go away. The latest round of brinkmanship shaking apart a papier mache administration has been a reminder of what most of the UK strives to forget. Northern Ireland might have the delights of the D’Hondt electoral system, just like Scotland. It too might be wrestling with issues of austerity, welfare cuts and economic growth. What it lacks, conspicuously, is anything resembling stable, functioning government.

No one should try to represent the latest crisis as just another of those Stormont things. In Unionist eyes, the question of whether the IRA continues to exist and murder touches the basis of power-sharing. The Provos’ statement a decade back, by which the organisation seemed to promise its dissolution, was fundamental – along with the decommissioning of weapons – to Unionist participation in the executive. If that was a lie (or can be presented as a lie) all bets are off.

Old IRA men do not cease to be old IRA men. Their ability to lay hands on weapons is not in doubt. Their readiness to kill one Kevin McGuigan because he was thought to have murdered a former commander named Jock Davison and might strike again is hardly worth debating.

But does the death of this man McGuigan mean the Provos are still in business? Opinions differ. This being Northern Ireland, opinions differ dramatically. Unionists have seized on a few probable truths to construct a larger, supposedly definitive proof. This says they have been sitting in government alongside people who are the allies – in the polite version – of unreformed terrorists.

Sinn Fein leaders and supporters retort by questioning the quality of that “proof”, and by observing that Unionists have been eager for this crisis for long enough. Deputy First Minister Martin McGuiness has condemned the killers as criminals (for whatever that might be worth) while the Police Service of Northern Ireland has given a view that is both plausible and unhelpful.

On the one hand, Chief Constable George Hamilton says IRA men were certainly involved in the killing of McGuigan. On the other, he doubts that the IRA sanctioned the murder. He also denies that the Provos have returned to any sort of war footing. There is no intelligence crossing the police chief’s desk to support the claim.

Nevertheless, furious Ulster Unionists have withdrawn their sole minister on the executive. First Minister Peter Robinson and his Democratic Unionists, with no desire to be outflanked on their side, have also “stepped aside” –meaning resigned – from ministerial posts, leaving just Arlene Foster, finance minister, as caretaker in a shadow administration. Significantly, however, the executive has not actually, formally collapsed.

Clear? That might be asking too much. This is a political arena in which profound arguments over George Osborne’s welfare cuts can come to a head in a row over a grubby backstreet murder. It is a political contest in which Mr Robinson can walk out while Sinn Fein stays put and all expect him to stage a “comeback” when the moment suits. It is a crisis that will probably culminate in an election. And that election will solve nothing at all.

Such – this week – is Northern Ireland’s devolution “settlement”. Power is shared by parties that despise one another. One, the DUP, would like nothing better than to see the arrangement ended. It hoped that by abandoning the executive in this row it could force Theresa Villiers, the Northern Ireland Secretary, to suspend institutions without sending voters to the polls. David Cameron, conscious of the Irish government’s role (thanks to the British-Irish Agreement) has no interest in that “solution”.

So there will be meetings on Monday. The idea, as ever, is to “bring the two sides together”. But on what terms? Sinn Fein regards itself as the injured party, defamed by unsubstantiated allegations while Unionists pull a political stunt. It would be content with elections. It has not brought down the executive. Just as important, north and south of the border, it has not accepted welfare cuts.

Mr Robinson continues to maintain that he will have no truck with terrorism or its apologists. His party shares power, he maintains, solely because Republicanism has abjured the gun. What the DUP leader fails to address are the kinds of issue that would be elementary elsewhere.

How is Northern Ireland faring amid this chaos? To what extent can shared, devolved power be said to have worked for the people of the province? While Unionists and Republicans squabble, Northern Ireland still has the worst unemployment rate in the UK. Near 20 per cent of its 18-to-25 year olds are without jobs while productivity for those in work, in terms of gross value added per hour, is still only around 82 per cent of the UK average.

Old ills, no doubt, born of the bad old days. But for how much longer can that be said while the parties contest their precious points of principle, stage walkouts, and struggle just to keep Northern Ireland’s Assembly in business. How long is too long? Peace, peace on an official terms, peace as a cottage industry, has been the rule in Northern Ireland for 18 years now.

Whether the IRA is still in business is not a question that can be ignored just to keep the devolution show on the road. That is not in dispute. The eagerness to seize on conjectured cause and effect and use government as the stage for ancient melodramas is another matter. Where does Mr Robinson think all this will lead? With institutions and an assembly suspended yet again?

After 18 difficult years, that’s not much of a prospectus for the future. It bears no resemblance to stable government. If London won’t take charge and Stormont cannot function, what truly remains of Northern Ireland’s devolution?