Stormont crisis: Why did Sinn Fein decide to vote against Welfare Bill?
How scared should a unionist be? What chance is there now that power sharing can work? The statement by Martin McGuinness yesterday, announcing that his party would vote against welfare reform, effectively scuppering the Stormont House Agreement which is predicated on it, had a familiar ring to it.
It sounded a bit like the Canary Wharf bomb, the London docklands blast that ended the first IRA ceasefire in February 1996.
While that attack was being planned, Adams and McGuinness had been meeting the Taoiseach and President Clinton and others, warning them about difficulties in the peace process and urging the Prime Minister John Major to get on with starting talks.
Then the IRA ended its ceasefire with a massive explosion in London followed by more in Manchester and in Theipval Barracks - and more still that didn't work out as planned.
And the big question then, as today, was: are they serious?
Well, they were, up to a point.
Implied in the whole republican approach was the message that no deal would be easy and that the movement would fight long and hard on key principles.
We can now say confidently in retrospect that the IRA under the leadership of Gerry Adams and Martin McGuinness had no intention whatsoever of decommissioning its arsenal, ever. Certainly not before, during or until a very long time after the Good Friday Agreement, and then only when its options had been closed down.
Nor had they any intention of recognising the police force and even seven years after Patten, Tony Blair tried to get them into a deal with the DUP without their assent to the PSNI.
All of this tells you that the republican movement always felt it had another hand to play throughout the whole peace process. It always behaved as if it had an alternative to agreement.
Some thought in 1994 that peace was in the bag bar the details and a bit of grandstanding. It wasn't. It could have collapsed at any time and republicans were playing so hard in negotiations that they often appeared not actually to need the thing to work.
That was all settled eight years ago. Except that we had routine existential crises for the agreement and the institutions afterwards.
We almost had a collapse over the failure of the Executive to agree the devolution of policing and justice. We had another crisis when the DUP threw a wobbler over the On The Run letters.
Then we had the Sinn Fein stand-off on welfare reform and a deal which seemed to just pull Stormont out of the fire at the last moment before Christmas, echoing the failed Haass talks of the Christmas before.
What is one to make of all this? One might suppose, easily, that the political system in Northern Ireland is addicted to crisis.
For those of us dependent on stable government, this is starting to feel like the turbulence of life with an alcoholic parent. There must come a point at which people will just get so fed up that they wish it would all stop, that they start to think that anything is preferable.
Sinn Fein may not, in fact, be addicted to crisis but they do manage it better than anyone else. They do have the gall for it.
Martin McGuinness was keen yesterday to emphasise that this crisis took shape before the Ard Fheis at the weekend. He appears to have been trying to scupper any suggestion that he panicked in Derry, or was given a talking to by Gerry Adams, confronted by the charge that Sinn Fein was implementing austerity in the North while challenging it in the South.
But maybe that is the full explanation of this. Maybe it has dawned on the party that in slashing services and triggering massive strike action later this week it is now the target of the unions and the workers.
Has McGuinness suddenly seen more clearly what should have been obvious before, that the striking workers on Friday will be presenting Sinn Fein as the destroyer of jobs. Is he reflecting on how badly that will look in Dublin where Gerry Adams is insisting that Sinn Fein will create jobs in the pubic sector and fund services by taxing the better off?
Just last weekend Sinn Fein held its Ard Fheis in Derry and it was a merry occasion. There was no sense of the party being on the brink of crashing the institutions or putting devolution in jeopardy.
The delegates were conscious of the embarrassing charge that they were a party of austerity in the North but Gerry Adams had an answer for that - blame the Tories. And in his presidential address he was bullish and confident, setting out the argument that no one would have their benefits cut.
If they have only just worked out that the £564m over the next six years, allowed for in the Stormont House Agreement, doesn't protect all claimants in perpetuity then that looks like incompetence. And if McGuinness really has just wet himself at the thought of undermining the party's project in the South, then that makes him look like a leader who is incapable of making decisions and holding to them through a storm.
But Sinn Fein is a southern party now and it may simply be that even the Stormont Executive is expendable for the sake of its growth and the pitch for power in Dublin.
As on the many past occasions when Sinn Fein brought the political system to the brink of collapse, you have to wonder if they are content that they have sufficient room for growth and influence even without Stormont.
For years they conducted negotiations on the presumption that others needed their assent to a deal more than they needed the deal themselves.
And that may simply be true.
Without Stormont they will have the big super-councils. In three of them they will be able to rule by majority vote. They'll have no need to get unionist assent to Irish language name changes or flying the tricolour. They can call their play-parks whatever they like.
And the dread reality may be that that is the kind of politics they are most comfortable with - defending identity rather than making practical decisions.
In the councils they can make half of Northern Ireland look more Irish and they can pitch in time for devolution of greater powers to local government, having turned Stormont into a black hole.
You never know with Sinn Fein if this is all accidental or planned, the fruits of deft conspiracy or just an awful blunder on the road to making Gerry Adams the president of Ireland.