A couple of weeks ago, there was a rather sadly predictable report of the reaction from some ultra-conservative Christian groups to the BBC's advance publicity for its dramatisation of the passion of Jesus. The author and producer had underlined the fact that they were presenting a fairly nuanced view of the characters of the 'villains' of the story like Judas and Pilate; the Christian critics responded by complaining that this was being unfaithful to the Bible. These characters were bad, and that was an end of it.

Viewers of the series will have their own judgement. But the alarming thing is that anyone should think that the story of Jesus' death is a story about the triumph of bad men over good ones – with the implication that if we'd been there we would have been on the side of the good ones.

It's not only that the biblical story – especially St John's Gospel – shows us just the mixed motives that can be seen in figures like Pilate and the High Priest.

Much more importantly, the entire message of the Bible on this point is that the problem begins with us, not them. Jesus is killed because people who think they are good are in fact trapped in self-deception and unable to get out of the groove of their self-justifying behaviour. And the New Testament invites every reader to recognise this in himself or herself.

In recent years a number of Christian writers – inspired by the French critic and philosopher, Rene Girard - have stressed with new urgency how the Bible shows the way in which groups and societies work out their fears and frustrations by finding scapegoats.

Because we compete for the same goods and comforts, we need to sustain our competition with our rivals and maintain distance from them. But to stop this getting completely out of hand ('the war of all against all'), we unite with our rivals to identify the cause of the scarcity that makes us compete against each other with some outside presence we can all agree to hate.

Just as the BBC drama suggested, Jesus' context was one where Judaeans and Romans equally lived in fear of each other, dreading an explosion of violence that would be destructive for everyone. Their leaders sweated over compromises and strategies to avoid this. In such a context, Jesus offered a perfect excuse for them to join in a liberating act of bloodletting which eliminated a single common enemy. The spiral of fear was halted briefly.

Frequently in this mechanism the victim has little or nothing to do the initial conflict itself. But in the case of Jesus, the victim is not only wholly innocent; he is the embodiment of a grace or mercy that could in principle change the whole frame of reference that traps people in rivalry and mutual terror.

Thus the scapegoat mechanism is exposed for what it is – an arbitrary release of tension that makes no difference to the underlying problem. And if you want to address the underlying problem, perhaps you should start listening to the victim.

For many of our contemporaries, the Christian message is either a matter of unwelcome moral nagging or a set of appealing but finally irrelevant legends. If it has a place in our public life or our national institutions, it is on the basis of a slightly grudging recognition that 'it does a lot of good work' and represents something about continuity with our past.

But what if the Christian story offered more than this? What if it proposed a way of understanding some of the most pervasive and dangerous mechanisms in human relationships, interpersonal or international?

It doesn't take much imagination to see how internally divided societies find brief moments of unity when they have successfully identified some other group as the real source of their own insecurity. Look at any major conflict in the world at the moment and the mechanism is clear enough. Repressive and insecure states in the Islamic world demonise a mythical Christian 'West', and culturally confused, sceptical and frightened European and North American societies cling to the picture of a global militant Islam, determined to 'destroy our way of life.'

Two fragile and intensely quarrelsome societies in the Holy Land find some security in at least knowing that there is an enemy they can all hate on the other side of the wall. A crumbling dictatorship in Zimbabwe steps up the rhetoric of loathing and resentment towards the colonial powers that create the poverty and the shortages. Nearer home, disadvantaged communities make sense of their situation by blaming migrants and asylum seekers.

It's not that the fears involved are unreal. Global terrorism is a threat, Israel and Palestine really do menace each other's existence, colonialism isn't an innocent legacy, and so on. But the exploitation of these real fears to provide a 'solution' to more basic problems both breeds collective untruthfulness and makes any rational handling of such external fears infinitely harder. It breeds a mentality that always seeks to mirror the one who is threatening you. It generates the 'zero-sum game' that condemns so many negotiations to futility. Worst of all, it gives a fragile society an interest in keeping some sorts of external conflict going. Consciously or not, political leaders in a variety of contexts are reluctant to let go of an enemy that has become indispensable to their own stability.

The claim of Christianity is both that this mechanism is universal, ingrained in how we learn to behave as human beings, and that it is capable of changing.

It changes when we recognise our complicity and when we listen to what the unique divine scapegoat says: that you do not have to see the rival as a threat to everything, that it is possible to believe that certain values will survive whatever happens in this earth's history because they reflect the reality of an eternal God; that letting go of the obsessions of memory and resentment is release, not betrayal.

People may or may not grasp what is meant by the resolution that the Christian message offers. But at least it is possible that they will see the entire scheme as a structure within which they – we - can understand some of what most lethally imprisons us in our relationships, individual and collective. We may acquire a crucial tool for exposing the evasions on which our lives and our political systems are so often built.

Yes, the Christian Church itself has been guilty of colossal evasion, colluding in just those scapegoating mechanisms it exists to overcome. Its shameful record of antisemitism is the most dramatic reversal of the genuine story it has to tell, the most dramatic example of claiming that the killing of Jesus was indeed about them and not us.

But it keeps alive that story. Every human society needs it to be told again and again, listening to the question it puts, whether or not people identify with Christianity's answer. The point of the Church's presence in our culture is not to be a decorative annex to the heritage industry, but to help us see certain things we'd rather not about common responsibility - and the costly way to a common hope.

© Rowan Williams 2008