Shooting policemen is a despicable but ancient Irish custom. It has gone on for a long time. It has its roots deeply planted in the history of this island. Those roots first flourished in the heat of disaffection with Government. For centuries it was held to be a patriotic duty to attack the Government and the police were its most visible arm.
None of these attacks on the police have displayed any element of nobility. Mostly they have been hole-in-the-corner affairs, executed by gunmen lurking in the hedgerow of a country lane: like the murderous attack on Constables McDonald and O'Connell at Soloheadbeg, Co Tipperary, on January 21, 1919. Both were well-known, and reputedly popular, local figures. McDonald had been 30 years in the force and had a large family. They were escorting two county council employees driving a cart-load of gelignite to the local quarry.
Eight volunteers, lying in hiding by the roadside, held them up and then shot them down. The deed is often held to mark the real beginning of the Anglo-Irish War which led to the Treaty of 1921. This is a bit specious, as policemen of the RIC had been shot and killed before - as had volunteers.
The Soloheadbeg killings, though, happened to coincide with the first sitting on the same day of the first Dail in the Dublin Mansion House, consisting in large part of the Sinn Fein MPs just elected to the House of Commons in the general election of December 1918.
Some, Sinn Fein or not, were appalled at the Co Tipperary murders. The volunteers, soon to be popularly styled the IRA, thought differently. One of the ambushers, Dan Breen, said afterwards that they were convinced it was necessary to light the fuse if anything was to be achieved.
He feared "the volunteers were in great danger of becoming merely a political adjunct to the Sinn Fein organisation ... It was high time we did a bit of the pushing".
The Soloheadbeg murders are still the subject of an annual commemoration, where a crowd of hundreds of locals are addressed by Fianna Fail and Fine Gael worthies, the mood being set by the Sean Treacy Pipe Band, named after one of Breen's fellow volunteers on the day: he who actually shot the policemen.
Indeed, the parallel with our own time is not to be avoided. The would-be murderers of policemen at this moment are also intent on lighting the fuse. They eschew the political path. Substitute for that first Dail a Stormont Assembly with Sinn Fein ministers and you get my drift. What the gunmen, rejected by the electorate, overlook is that times have changed.
It is indeed true that the Agreement which the rival parties have bought into is - like the Treaty of 1921 - an imperfect instrument. It prostitutes any notion of reputable democracy by constructing a Government denied an Opposition.
It involves a multi-coloured ministry whose luminaries slag each other off under the media spotlight. One is left surmising what meetings of the pseudo-cabinet must be like.
St Andrews sought to curb the excesses of unilateral ministerial action which occurred under Trimble and Mallon. But future policy collisions are inevitable: each will test the flawed fabric of the top-heavy structure.
The decisive factor remains that the deal was the only saleable product, based as it was on equality of deprivation: neither side got what it professed to want, a well-lubricated runway into a united Ireland or a Northern Ireland more integrated with Great Britain.
Instead we have a heavily-institutionalised halfway house - but one where the ordering of the institutions, in the Assembly, the police, the forest of quangos and the rest, has emphasised the sectarian divide rather than blurred it.
This has shaded all too comfortably into an obsession with the torture of the immediate past. Understandable pleas for its victims have too often declined into exercises in tribal self-justification.
There has even been a row over choosing a victims commissioner, while the notion of a reconciliation commission refuses to go away. Many feel it would be better forgotten because it owes too much to fraudulent parallels with South Africa.
It may be harsh to say so, but Northern Ireland sorely needs to climb out of the slough of its evil past rather than to wallow in it. Those who accept that tend to find the endless, obsessive commemoration deeply depressing. In this the addiction of television news to human distress is no help.