How on earth did Sinn Fein and DUP to get this point within weeks?
What began as a financial scandal in Northern Ireland is turning into a full-scale constitutional crisis. Surveying the Democratic Unionists and Sinn Fein today, we might well marvel at how they tolerated power-sharing with each other for so long.
Once again the most divisive attitudes surface. One side competes with the other in the exchange of insults and personal abuse.
As an election looms, a brick wall awaits at the end of another cul-de-sac. Everyone knows that the issues of the Irish language, the legacy of the past, equality and the RHI debacle will not be resolved by a simple vote.
Many in the community, unionist and nationalist alike, are left in a state of shock. So too, are the British and Irish Governments, accused of taking their eye off the ball.
However, like the rest of us, London and Dublin hardly saw any election coming.
Their intervention appears too late to prevent a political divorce which threatens to reverse years of progress and reopen the whole issue of how Northern Ireland is governed.
The unionist community doesn't know what has hit it. Why? Many had high hopes for Arlene Foster. Young and articulate, she promised a bright future, buying into power-sharing, widening the unionist appeal, and building respect across the community at large.
Her life bridged a troubled past to the peaceful present, a victim of violence in her childhood, an impressive promoter of investment in her role as an Executive minister.
Many felt she had the right credentials to bridge the gap between traditional Protestant/Orange unionism and the increasingly secular world of today's generation.
Above all, she seemed sufficiently assured that despite the IRA's attempts to kill her and her father, she wouldn't let that stand in the way of doing business with Martin McGuinness.
As for McGuinness, despite his past history in the IRA, unionists had a sneaking respect for his homespun phlegmatic manner and his commitment to power-sharing.
Ian Paisley and Peter Robinson had done business with him. He and the Queen had shaken hands on more than one occasion.
Until this week's seismic events at Stormont, it was unthinkable that Arlene Foster would not be capable of doing the same.
So how come today, within a few short weeks of Arlene Foster and Martin McGuinness writing a joint article in this newspaper, proclaiming their determination to work together, we are in this mess?
How come an Executive which, according to Mrs Foster, was working better than ever, has unravelled so bitterly and quickly?
The dismantling of so many aspirations is played out before our very eyes and ringing in our ears, in print and on the airwaves.
The DUP might argue that Sinn Fein was always going to do as they have done at some point.
However, the evidence suggests otherwise, not least in the liaison which McGuinness and Foster emphasised through the Fresh Start programme for Government.
When the RHI scandal surfaced, in the public's mind through the BBC Spotlight programme and subsequent revelations from Stephen Nolan, Arlene Foster and the DUP adopted the strategy of muscling it out. This has not played well with many unionists, never mind nationalists.
In hindsight, Foster might now consider that she did herself no favours on an issue of such enormous public concern. If she had been a minister at Westminster, almost certainly, she would have resigned, been pressed to resign or, at the very least, been urged to stand aside while an inquiry took place.
Instead she dug in and portrayed the RHI scandal as the fault of others, be it the consultants who advised on the scheme, the officials who administered it, or her former ministerial colleague, Jonathan Bell.
Ironically, the evidence in any inquiry may well concur with her conclusions, but her unwillingness to see the need for any act of contrition on her part, such as standing aside from her office, has contributed to the current situation.
Perhaps she was advised to adopt her hard-nosed approach if only to copper-fasten authority as a relatively new leader of the DUP.
On the narrow ground of her party colleagues, she has unanimous backing. But at what cost to her image and authority as First Minister?
Certainly, she has awakened a sense of unease in the wider community with a deepening of unionist divisions and the prospect of a very bitter electoral battle.
Suddenly, the RHI crisis has transformed amiable, amenable Arlene Foster, the minister who presented the acceptable face of the DUP to the wider community, into Arlene Foster, accused of arrogance and aggressiveness and not just by nationalists and republicans.
Worse has followed with the DUP battening down the hatches around the leader. The party refuses to countenance any criticism, wheeling out its foot soldiers onto the phone-in shows and engaging, as the Communities Minister Paul Givan has done, in the particularly insensitive withdrawal of financial support at Christmas from an Irish language scheme for children.
That he has now restored the funding seems but an act of belated redress.
Disdain and disregard for anyone who dares to link the DUP with the decisions over RHI has become the party's strategy.
In closing ranks it has failed to understand that many more people than diehard republicans and nationalists, have been unimpressed by the former First Minister's lack of contriteness. As for Sinn Fein, it has bounced Northern Ireland into an election, at the cost of another £5m and six weeks of further distraction, during which relations between unionists and nationalists will deteriorate and after which, Stormont may never be the same again.
The crisis over RHI and, in particular, how it has been handled by the former First Minister and her party has enabled Sinn Fein to take the high moral ground and to reopen the whole future governance of Northern Ireland. The SDLP is even emboldened to call for joint authority if Stormont cannot be put back together again.
Perhaps, much of today's crisis could have been avoided had the RHI scandal been handled better.
The hard-earned lesson of Northern Ireland over the past half century is that if unionists do not give enough and nationalists demand too much, the community at large is left to pick up the pieces.
When Arlene Foster took over the leadership of the DUP, she prided herself on promoting a new generation of ministers and MLAs, many under 40.
However, faced with the fall-out from the biggest financial crisis ever to hit Northern Ireland, her Young Turks, such as Paul Givan, still appear to have quite a lot to learn about community sensitivities in a divided society.