Their same-sex marriage stance exposes Sinn Fein hypocrisy over failed talks
Where are the "more responsible, more mature politics" Martin McGuinness spoke of only last year, wonders Eilis O'Hanlon
So here we are, back at Square One again. No matter how far Northern Ireland politics seems to progress, it always returns to that familiar address in the end.
Lesson One: Tearing down Stormont is a lot easier than putting it back together.
Who'd have guessed? (Apart, that is, from anyone with a working brain).
Lesson Two: Deadlines mean nothing.
This should all have been over last Thursday.
Instead the talks were given a few extra days, because that's sometimes worked in the past, so what harm was there in trying the same tactic?
The harm is that no one takes it seriously any more when told that they must reach agreement or else.
It's like one of those films where the maverick cop begs for more time to catch the bad guy, and the chief gives him 24 hours, but not a second more, warning that they'll both be for the chop if he doesn't deliver.
If the cop kept coming back for another 24 hours, and the chief kept giving in, the cinema audience would eventually walk out in disgust.
There has to be an "or else", otherwise the whole process becomes meaningless.
Lesson Three: The process has become meaningless.
Yesterday's Press conferences could have been recorded at any point in the last six months.
How would we have known the difference? The sun was out. That was all. Otherwise it might have been January again.
There was Arlene Foster, insisting that Sinn Fein has "a shopping list that seems to get longer", and is not showing respect to the differing traditions. There was Sinn Fein, accusing the DUP of "delaying and blocking the rights-based issues" which it claims are causing the deadlock.
The Secretary of State, meanwhile, was in the House of Commons, telling MPs that a deal might still be possible this week.
His bizarrely optimistic performance suggested that James Brokenshire has either not been paying attention lately, or else took the opportunity of a brief return to London to catch up on the first day's play at Wimbledon and missed the memo telling him it was all going belly up.
Everyone knows what's going to happen next. Talks will be suspended to get over the Twelfth of July celebrations; everyone will go on holiday for a few weeks to keep up the pretence that they actually have proper jobs from which a holiday is needed; then they'll come back at the end of August and start again.
If that doesn't work? (And there's no reason for optimism that it will). Well, direct rule appears to be off the table, partly because those who are paid handsomely to make Stormont work shouldn't be allowed to wriggle out of their responsibilities that easily.
However, it's mainly because the British Government has more than enough on its plate right now, what with falling apart at the seams every few hours. Taking on the added burden of Ulster is the last thing London wants or needs.
Only Owen Smith, Labour's new Shadow Secretary of State, begs to differ. He even suggested yesterday that the Prime Minister herself should "get a plane to Belfast" to lend a hand.
Is he kidding? What evidence is there that Theresa May's personal involvement solves any crisis? She took sole control of the recent election and went from 20 points ahead in the polls to losing a parliamentary majority.
As for Dublin's new Minister for Foreign Affairs, Simon Coveney, he appears to be under the impression that his job title is Minister for Agreeing With Everything Gerry Adams Says.
Lesson Four: outside help is not a magic wand.
It may get to the stage where an "independent chair" will need to be drafted in to give the shambles at Stormont the illusion of professionalism.
But if there really is such a gaping divide between the two sides, there's little that bringing in a fresh face can achieve except to further convince participants that they're so important their petty squabbles must be indulged with the full trappings of international diplomacy. More talks it is then, followed by another election, despite there being no appetite whatsoever for one on the ground.
Then there will be further talks, at which compromise will be made harder still if, as looks likely, the vote sees a further hardening of the unionist and republican vote. After that, Christmas. Soon the one year anniversary of the entirely pointless and avoidable collapse of Stormont will be round the corner.
And what will the long adjournment have achieved? Politicians are merely buying time to posture, when they could be using the cash which Arlene Foster brought back from Downing Street to buy more healthcare, education, infrastructure.
As it stands, that money will end up being allocated by faceless officials once something called the "Appropriations Bill" is passed at Westminster. The grim undertones of that word "appropriation" should be enough to remind them all what's at stake.
Lesson Five: Either use power responsibly, or it will be taken, seized, swiped, or otherwise expropriated from you.
It's the stand-off over same sex marriage which best highlights how absurd and dishonest and theatrical the situation has become.
Sinn Fein insists that it can't possibly go back into government in the absence of what it calls "marriage equality" - but former Deputy First Minister Martin McGuinness worked alongside Ian Paisley and Peter Robinson, neither of whom supported gay marriage, much less legislated for it.
In his statement last May welcoming the new Assembly, McGuinness didn't mention same-sex marriage once. It certainly wasn't a precondition.
In fact, when Alliance at that time tried to put pressure on the Executive to stop using "petitions of concern" to block such issues, the two parties dug in their heels and resisted. Nor did Gerry Adams seem unduly concerned when he jetted off for the funeral of his "hero" Fidel Castro that Cuba doesn't recognise gay marriage either.
Suddenly republicans would have everyone believe they're so committed to gay rights that they'd rather leave Northern Ireland rudderless during Brexit negotiations than accept it may take a bit longer to get same-sex marriage here than elsewhere.
Lesson Six: What's needed right now is a "more responsible, more mature politics".
Don't take my word for it. That's what Martin McGuinness said last year when entering the Executive alongside Arlene Foster.
Was he wrong then, or are his successors wrong now? It has to be one or the other.