The 1987 general election in Scotland thundered to a debate about an impending doomsday scenario.
That theoretical involved Scotland overwhelmingly voting Labour and ending up with a Conservative government virtue of votes south of the border.
In the end Scotland returned 50 Labour MPs out of 72 but they remained relatively impotent as Mrs Thatcher celebrated a third term.
Election 2019 in Scotland represents a sort of Doomsday Chapter 2. Scotland decisively votes for the SNP and yet only the Conservative UK mandate would appear to count for anything.
The SNP’s landslide in Scotland is psephologically more impressive than Boris Johnson’s in the UK. And yet in the impending clash of the mandates over the two great constitutional issues of our time, only one is likely to prevail.
Brexit will happen, that debate has now gone the way of the dodo. But it is a start of a continuing process rooted deep in the politics of constitutional uncertainty.
As Michel Barnier’s leaked comments this week imply, the Commons passing the withdrawal agreement is not an end but a beginning of a wider negotiation.
As Mr Johnson delivers what Nicola Sturgeon deplores she will demand the power to hold a new independence referendum next year.
The coming weeks will determine if the Prime Minister’s inflexible ‘no’ still stands or whether he seeks to shift ground. My bet is that he holds the line even in the face of Conservative losses north of the border.
Unless there is a strategy other than issuing demands to respect the election result in Scotland, I am not sure what the SNP leader can do to enforce indyref2. She may have to live creatively and dangerously on that front.
If Mr Johnson says ‘no’ he might actually widen and harden the base of electors who embrace independence helping to deliver the very outcome so abhorrent to unionists.
Make no mistake, today we are in the most acute political crisis of the devolved era and one where it is the Prime Minister who is playing the high wire act.
The historians will record that election 2019 was driven by two great constitutional questions and one in which the result partially answered one and refused to consider the other.
Over five years on from IndyRef1 and still the country is divided. It is a debate of no middle ground and of an uncertain end but it is one that is the stuff of a genuine constitutional crisis.