Onus is on intelligence services to arrest these vigilantes on basis of other criminal activities
So, this is Christmas, and what have you done? Another year over and a new one just begun."
It is not generally known that John Lennon's lyric for Christmas and the New Year bears the sub-title 'War is Over'.
Well, it's not over in some parts of Northern Ireland.
In answer to John's question, there are several dozen men, if they may be called that, who could reminisce round the fire: 'Well in 2018 I fired bullets into the legs and arms of anti-social elements in our estate'.
Or, 'me and my fellow volunteers beat the s*** out of drug dealers'.
Proud boasts indeed, though I'm prepared to bet there won't be many ballads by this time next year celebrating the exploits of the 'Kneecappers' of the North.
It is true that the levels of paramilitary violence against members of their own community have fallen heavily since the 1990s, when they reached record heights during the early stages of the peace process.
It is also true that responsibility for the majority of attacks has shifted from the republican to the loyalist side of the house.
But what is really astonishing is that 20 years after the signing of the Good Friday Agreement, Northern Ireland is still the black spot in Western Europe for the most serious human rights' abuses.
It is a curious thing, as Detective Chief Superintendent Murray points out, that republicans prefer to use guns rather than bats and iron bars, opting for paramilitary-style shootings rather than beatings.
The explanation may be that dissident republicans have a more coherent ideology deriving from the Easter Rising of 1916.
They are, after all, soldiers of the 'Irish Republic' - a republic as yet unrealised - so the use of the gun is appropriate.
To many in this society they may be the rag ends of republican paramilitarism, desperately seeking status as 'local heroes', but their self-image requires military-style trappings.
Loyalism, by contrast, faces the dilemma of 'loyal to what and to whom?', and its traditions of paramilitarism are less highly developed.
Both loyalist and republican gangs are deeply involved in criminality of all kinds, from smuggling and extortion to direct or indirect involvement in the drugs trade.
Self-image matters in many ways. The paramilitary persona is a brittle one.
To cross a self-styled volunteer, of the loyalist or republican variety, is exceedingly dangerous. As one victim put it, they come after you in droves.
We will never know how many vigilante-style shootings or beatings have had to do with personal slights or rivalry which are later dressed up in self-serving rhetoric about anti-social behaviour and community defence.
'Hard men' and 'top dogs' must not be made look foolish.
The PSNI is correct to highlight the huge problems in getting victims to give evidence in court.
But to talk is to invite further retribution, and possibly a death sentence.
It is easy to suggest that victims might move elsewhere but many of these, particularly the child victims, do not have the social skills or the social connections to make a life for themselves in the alien environments of Scotland, England or the south of Ireland.
But surely the intelligence services, who clearly have heavily infiltrated most of the gangs - as is evidenced by the limited number of armed attacks on the police in recent years - should be able to pinpoint the small number of key figures and indict them, not on 'punishments' but on the basis of other criminal activity?
Liam Kennedy is professor emeritus of history at Queen's University