WHAT is more important: justice or peace? Answer in 30 seconds, please, as one radio presenter required in one of those preposterous debates that the Today programme on Radio 4 is always starting, and then realising that it does not have the time to do properly, if it is to fit in the next item on birdsong.

The issue is taken more seriously in Northern Ireland, where the Sinn Féin president, Gerry Adams, was recently released by the police, after being questioned for four days about one of the most horrendous murders in the decades-long civil war euphemistically known as the Troubles.

In 1972, Jean McConville, a 37-year-old widow and mother of ten children, was dragged from her home by 12 IRA men, in front of her children, and executed as an informer. Afterwards, her 11-year-old son was tied up, hooded, beaten with sticks, and told that he would be killed if he ever revealed the names of those who had taken his mother, whose body was only found 31 years later.

What has reopened this wound has been an oral history project at Boston College, in the United States, which has interviewed former paramilitaries. It promised not to publish the material until after the terrorists' death. But a book containing the accounts of two who have since died led the Northern Ireland police to take court action in the US to order the handover of all the material.

Many make a category mistake here. The raw material of history is not the same thing as information that would constitute evidence in a court of law. Its candid confessional material inevitably includes hearsay, colour, mood, and deeper communal psychologies, which are not admissible evidence. Four decades on, reportsare subject to the fallibility and embroidery of memory. They are vehicles for self-justification and score-settling. And dead witnesses cannot be cross-examined. Even so, one former IRA man, Ivor Bell, aged 77, has been charged with aiding and abetting murder as a result. And Mr Adams was arrested and questioned, although not charged.

There is nothing new in the tension between justice and peace. The Irish playwright Frank McGuinness reminded us of that in a more substantial radio discussion on Start the Week, prompted by his reworking of the Oedipus plays by Sophocles for a new opera, Thebans. He has shifted to the centre of the story the dilemma posed by Antigone in her clash with the ruler, Creon, over the burial of her brother. It embodies the same conflict between an individual who needs justice, and a community which requires a settlement for peace.

What is interesting is that, for Sophocles, Creon represented a necessary modernity, and Antigone the vestige of some primitive individualism. Our own age seems to have inverted those values. Today, the loudest cries - and most heart-rending in the case of the ten orphaned McConville children - are for justice for the victims. And yet the political reality is that, as a society, we have already made a judgement in which, to use the words of Thabo Mbeki, in post-apartheid South Africa, justice for individuals "cannot be allowed to trump peace" for the collective.

This throws up all manner of ideological tensions; for the common good is not the same as the good of the majority: it requires the protection of minorities. But it does assert the need for balance, especially in a community which is still an uneasy coalition in tension, and where empathies remain partial. "Let justice be done, though the heavens fall," is a deontological delusion. Facing up to this is part of the painful political compromise that was not called the Good Friday Agreement for nothing.