It was not by accident that the Belfast Agreement was rooted in the principle of dual consent by the unionist and nationalist communities in Northern Ireland, or provided that that rule should apply above all to the election of the First Minister and Deputy First Minister in the new Stormont.
It was by all accounts the SDLP's Mark Durkan and SΘamus Mallon who insisted upon it in the Strand One negotiations, only finally concluded in the early hours of that historic morning in April 1998. Some of those involved recall Mr Mallon's determination that this basic principle - that the First and Deputy First Ministers should command a majority of both sides - was the one the people would most easily and readily understand.
In simple terms, it gave the SDLP the assurance (at least at that point) that there would be no outcome of which it did not approve. It also seemed to offer unionists a guarantee that they would never have to revisit their 1974 nightmare, in which a minority of unionists might seek to sustain an Executive against the wishes of a majority of the pro-Union population.
Elsewhere, the agreement would provide for alternative forms of voting, allowing decision-making by simple majority or, in respect of certain key matters, by way of a weighted 60 per cent majority comprising at least 40 per cent of unionists and nationalists.
These variations might be reasoned now to be anomalous. Indeed, British sources have argued precisely that in the last 24 hours, depicting the conclusion of the 1998 negotiation in this regard as almost accidental, a detail which might really have been finessed in a number of different ways. It is true that much in the final stages was completed in something of a fuss and a panic.
However, this was not an accident. On the most fundamental issue of all - the leadership of the power-sharing government - the SDLP prevailed, and the dual consent principle was entrenched in British law.
Last Friday at Stormont, the consent of the unionist community, reflected by the votes of its elected representatives, was formally withdrawn, yet this unwelcome and unhelpful new fact of political life is to be simply disregarded.
No matter that the majority unionist No to Mr Trimble's restoration as First Minister makes real the long-threatened crisis of democracy at the heart of the agreement. Courtesy of a deal with the Alliance Party, the power-sharing administration is set to continue with Mr Trimble's unionists as minority shareholders.
Determinedly non-sectarian and non-tribal, Alliance members are to redesignate themselves as unionists for the purpose of reversing Friday's result. The distaste many unionists will feel at this spectacle is matched only by the rising revulsion inside the Alliance Party itself. Its leader, Mr David Ford, was quoted yesterday as saying: "I think many of us would find it difficult to stomach being either a unionist or a nationalist for more than 24 hours."
It was also Mr Ford who volunteered the essential context.
What he was talking about, he told BBC Radio 4, was "a short-term fix". Heaping scorn on Alliance, one nationalist sympathiser privately described the manoeuvre as "anti-democratic" and "a fundamental breach of the agreement". Plainly, however, what works is what matters.
Pragmatism rules, and probably a good thing, too, in the minds of the majority throughout these islands who want the agreement to work and cannot for the life of them comprehend how two Ulster Unionist "mavericks" could threaten its very survival.
Indeed, to borrow from Harold Wilson's famous demand, just who do these people think they are? What right did they have to ignore the ruling of their own party executive? More to the point: by what insanity of the rule book could they stop Mr Trimble's return as First Minister when that is the manifest desire of more than 70 per cent of the entire Assembly?
Mr Ford yesterday sought to add to this state of confusion and disbelief, attributing Friday's result to a set of "byzantine rules" which his party had opposed all along. Mr Ford, however, knows very well the history of the agreement. It is perfectly true that Alliance members have argued against the system of designation of Assembly members as unionist or nationalist, by which the votes of the "Others" - Alliance and the Women's Coalition - are in effect of no value in any election for First and Deputy First Minister.
But he also knows the origins of dual consent, a process seemingly well enough understood before, now suddenly a byword for complexity and mystification.
As with so much else in the peace process, it can be credited to the retiring SDLP leader, Mr John Hume. For many lonely years, then finally with success, Mr Hume argued that simple majoritarianism would not work in a divided society.
Slowly, painfully, unionists came to embrace the concept of power-sharing, right down to a 50- 50 split of ministerial portfolios in the Executive.
Now they are being told a different form of majoritarianism might suffice after all, one first mooted by Sinn FΘin's Mr Mitchel McLaughlin earlier this year, in which unionists comprise a minority component of a ruling pro-agreement bloc.
It is not hard to understand why the Secretary of State, Dr John Reid, prefers this to the fresh Assembly election alternative.
The Northern Ireland Office calculates, perhaps correctly, that time will be its friend and that the DUP's moral outrage will subside as normal political life reasserts itself.
As they explained Dr Reid's decision to hold fire on his legal obligation to call an election pending today's vote, British sources could contemplate a bedding-down of the institutions over an 18-month period leading, hopefully, to a more benign scenario when the next scheduled Assembly elections take place.
However, senior Labour MP Mr Kevin McNamara says the introduction of looser rules now makes it impossible to forecast what would happen as a result of any future election.
While accepting that the promised rules review might be deadlocked, he told The Irish Times: "The real question is what is the agreement that has been made [with Alliance] on voting matters and will it dilute the need for majorities in both communities?"
While fervently opposed to what the DUP is attempting, Mr McNamara did not shy away from the conclusion that any alteration in the rules of this political engagement "automatically raises fundamental questions about parity of esteem for both communities".