NI welfare bill collapse: This is a crisis in more than name
As every trainee journalist knows there are five basic questions that must be answered before you do any story: Who?; What?; Why?; Where? and When?
The Who? with this story is easy - that's Sinn Féin.
The What? is that they have essentially pulled the rug from beneath the Welfare Reform Bill, the one everybody thought was sorted before this morning.
The Where? is straightforward as well - at Stormont as we got ready to watch the aforementioned bill have its final reading before passing into law. Not in Londonderry at the Sinn Féin Ard Fheis last weekend, when the party appeared to be congratulating itself on protecting the vulnerable through the mitigations written in the Stormont House Agreement
And the When? was right out of the blue around 11:00 GMT, with a news release inviting us to a Martin McGuinness news conference where there would be a "major announcement" on the Stormont House Agreement.
So far so straightforward. The difficult one is the Why? That's the one that has everyone at Stormont scratching their heads and asking how all of a sudden the institutions once more appear to be in peril.
Sinn Féin accused the DUP of "bad faith" and reneging on its "commitments in the Stormont House Agreement to protect the most vulnerable people in society."
But if that's the case why was none of this obvious at the Ard Fheis? How come this dropped from the sky with all the speed lacking at Christmas when the parties negotiated a way out of the crisis in hours, days and weeks of tortoise-like talks.
What's clear is that since Christmas, Sinn Féin and the DUP have operated what looked suspiciously like a non-agression pact.
While others parties lined up to accuse Sinn Féin of "rolling over" on welfare reform" the DUP conspicuously said no such thing.
Now those same parties are lining up to accuse Sinn Féin of doing a "U-turn" with theories ranging from they got their sums wrong to the one where the difficult balancing act of opposing cuts in the Republic of Ireland while overseeing them in Northern Ireland finally came to a head in meetings away from prying eyes behind the scenes in Derry.
The truth is no-one really knows. At least, no-one outside Sinn Féin.
But what is not in doubt is that this is a "crisis" in more than name.
Welfare reform and the Welfare Reform Bill are a vital component of the Stormont House Agreement.
Without agreement on welfare reform all the other constituent parts of the agreement are in serious doubt. Including the £700m loan from the Treasury to fund the public sector voluntary exit scheme and the devolution of corporation tax.
And when will the next tranche of fines for not implementing welfare reform - £114m - be triggered.
The bill has now been withdrawn so that it doesn't fall prey to the petition of concern put down by Sinn Féin and supported by the SDLP.
But does the time, the goodwill or the heart exist to renegotiate it?
Or are we heading for an assembly election with no guarantee that the new look chamber will offer any more hope of agreement than this one?
It's a mess. And it must further erode public confidence in institutions that didn't have much to begin with.
A weekend is indeed a very long time in Northern Irish politics.