The newly-released Cabinet papers in recent days have reminded us of the grim days of the Anglo Irish Agreement (AIA).
The 1985 deal gave Dublin a formal consultative say in how Northern Ireland was run.
It was an outrageous dilution of British sovereignty in Northern Ireland. That it was conceded by a prime minister as unionist as Margaret Thatcher made it all the more shocking.
With hindsight it is clear that unionist leaders at the time had both failed utterly to read the runes, but also failed to make the sort of influential friends in Westminster that they should have been cultivating.
Mrs Thatcher was said later to have bitterly regretted the AIA, and it is encouraging to think that might be true.
We now learn that Dublin felt after the AIA that the then secretary of State, Tom King, was outraged by the deal and distrustful of Dublin. He goes up in our assessment if so.
As one of the recently released cabinet papers have shown, London was despairing of Dublin’s extradition failures in the late 1980s. If mandarins had paid closer attention prior to 1985, that security failure would have been no surprise.
As a consequence of Dublin’s repeated refusals, known and fanatical IRA men found the Republic to be a safe haven. Many civilians died at the hands of these terrorists.
This is the pattern of Anglo Irish relations: Dublin agitates for nationalists, London plays neutral broker (at best – in 1985 it sided with John Hume behind the backs of unionists).
Now political leaders in the Republic are again demanding a public inquiry into one Troubles death: that of Pat Finucane.
And London, in response, is politely silent as ever.
There is no chance now of a Finucane probe, which would be a scandal given the vast number of IRA victims whose deaths deserve scrutiny. But there is a risk that the DUP, under pressure over RHI, agree to legacy inquests.
Conceding this Sinn Fein goal will be a huge mistake, and could lead to files on ex servicemen being sent to prosecutors.