It is so unusual for the divided political classes of Northern Ireland to agree on anything that when it happens observers feel like taking a closer look.

This week there was almost unanimous political criticism of the suggestion from Northern Ireland's Attorney General, John Larkin, that the investigation and prosecution of the crimes of the Troubles should end. The intensity of the reaction may be because there is a large grain of truth in what he said and because he has exposed the enduring failure of the Stormont Executive and of the Assembly to tackle the legacy of those crimes.

For the past two decades of peace-processing the politicians of Northern Ireland and the London and Dublin governments have talked much about the need to deal with the past. In reality, however, they have done little.

Overstretched system
It has fallen instead to an overstretched police and court system, to expensive one-off tribunals or inquiries, to victims' groups and to investigative journalism to probe, poke and contain the painful legacy of the Troubles.

In his own brash manner Larkin has exposed a hazardous weakness in the foundations of the peace process. His way of doing so has inevitably upset many victims and made many politicians uncomfortable. When the initial outcry has died down he will be seen to have made a useful contribution to advancing this debate.

Larkin’s comments are informed by the reality of where Northern Ireland’s criminal justice system is at. It is extraordinarily difficult to investigate and prosecute historic crimes even in ordinary circumstances. Memories fade or become distorted and evidence disappears.

These difficulties are compounded in Northern Ireland by the fact the initial investigations into many atrocities were inadequate. There were hundreds of murders a year at the height of the conflict, which meant investigative resources were thinly spread. Significant shifts in the legal framework implemented during the peace process have created additional difficulties in securing prosecutions.

The prospects of gathering viable forensic evidence, very limited in the first place, are further restricted by laws providing that decommissioned guns cannot be tested or that the bodies of the disappeared, if recovered, cannot be examined for evidential purposes.

Hundreds of those convicted of crimes have been released early under the Belfast Agreement, including many who served a small fraction of their sentence.

Even if those who committed the unsolved crimes could be identified, prosecuted and convicted the maximum sentence they would by law have to serve is two years.

In these circumstances continuing to suggest to victims or their families that those who committed these crimes will be identified and punished is cruel. Asking them to accept that this will not happen is harsh but honest.

Overreaching
The politicians have accused Larkin of overreaching his powers. What he had to say had a greater impact, of course, because he is the Attorney General but there is nothing in legislation or in precedent that restricts him from talking publicly on issues with such implications for the criminal justice system.

Larkin did no more than offer a view. His intervention was a contribution to the debate, albeit a provocative one. Unlike the politicians, he does not have to pander to a constituency.

Larkin has also been criticised for not discussing his views in advance with the Executive or with victim groups and for not waiting for the Haass process to conclude. These criticisms are a distraction from the central issue.

It seems in Northern Ireland there will always be some process or some future report people will say should be awaited. There is never an easy time to talk about these issues without treading on the sensitivities of victims. Archbishop Robin Eames and Denis Bradley, both very sensitive men, learned this when their report was published nearly five years ago. It was finalised after months of careful consideration and consultation but still generated controversy.

Eames and Bradley proposed a commission to probe unresolved cases followed by appropriate remembrance, by amnesty and accompanied by a notional compensation to all victims. None of these has been advanced. Politicians and policymakers simply ignored their report.

Larkin has called the politicians in Northern Ireland and the London and Dublin governments on their failure to agree a comprehensive process around dealing with the past. Their new found unity in response to his suggested solution should be channelled to agreeing and implementing meaningful proposals of their own.