To what political attitudes might Christian belief point? Can the decline of Christianity in rich western countries be reversed, and, if so, how? These are the main questions discussed in Shirley Williams's arrestingly titled essay "God and Caesar", based on lectures delivered at Notre Dame University in the United States in 2001. Currently the Liberal Democratic leader in the House of Lords, Shirley Williams is the most sympathetic figure in British politics today. She is also a practising Roman Catholic. But despite its grandiloquent title, God and Caesar is not about the relationship, historical or contemporary, between theology and politics. Rather it is the work of a career politician, who simply describes the origins of her own faith, tries to show how that faith has influenced her political beliefs, and asks us to consider what Christian belief might imply for political practice. Despite her attachment to Europe, she has also written a very English book. She looks at the world through English eyes, and ticks off its virtues and vices accordingly.
Williams recognises that western Europe is rapidly becoming de-Christianised. She rightly rejects the view that science is to blame, pointing out that the decline of worship has accelerated since the 1960s. And she rightly uses frequency of worship as the test of commitment, remarking that "the solidity of Christian belief is strongly related to the practice of religion". As she tells it, the decay of Christianity is a joint product of the decline in demand for church worship and a decline in the supply of clergy as other vocations become more attractive - a vicious circle in which the closure of churches progressively narrows both the demand for, and supply of, Christianity. Her explanation of this decline is sociological: urbanisation has increased people's distance from nature, and therefore from God; as material abundance increases, Christianity "can no longer rely on poverty and misery in this world as reasons for yearning for the next". She does not deal with the problem this type of explanation must pose for a believer: if belief depends on material conditions, what remains of the Christian claim to "true belief"? We do not say that physics is less true in rich than in poor countries.
This is the first of the secular "soft spots" in the book. The second arises with the class of remedies Williams offers for this situation, addressed specifically to the Roman Catholic Church: widen recruitment to the priesthood by accepting married priests, women priests and "homosexuals in stable relations" (that is, make the priesthood more attractive); and make it easier for the Church to retain its lay membership by allowing artificial contraception. While these are examples of good secular, not to say economic, reasoning, they lie uneasily with Williams's confession that "it was the huge claims and the huge demands made that drew me to the Church of Rome". Furthermore, given that the Church of England has been declining even faster than the Church of Rome, it is hard to understand why Williams believes that following in its footsteps will bring about its recovery.
It would be a crude oversimplification to say that Williams hopes to bring about the Kingdom of Heaven on earth. But she does wish that the Roman Catholic Church - her church - had been, and could be, more vigorous in the fight against the "structures of sin" that maintain poverty, exploitation, inequality and organised wickedness. She castigates the present pontiff, John Paul II, for having helped kill off "liberation theology" in Latin America; she calls Pius XII's silence in face of the Holocaust "one of the more shameful periods in the long history of the Church". These are judgements that many Catholics would share. But she never engages with the contrary argument that the Church's record of survival has depended on it taking very long views and not taking stands that endanger its survival as an institution.
The United States is a huge exception to the sociological rule of religious decline in wealthy societies. The richest country in the world is also one of the most religious.This baffles Shirley Williams, as well it might. Curiously, she does not consider a couple of plausible explanations: the role of religion in bonding together immigrant communities, and the underdevelopment, by European standards, of state-provided social services. The relative inequality of American society could be said to create both a greater need for religious consolation and a greater role for faith-based philanthropy.
The United States, particularly in its present incarnation, also poses a serious problem for Williams's view of what Christianity means for politics. Her church stands for the pacific, not martial virtues - "forgiveness, reconciliation, peace". Its social attitudes are generous - a tendency that she feels has been reinforced by the rise of women in public life, bringing with them an agenda of "soft" issues. The irony that it is secular Europe which is pacific and socially compassionate and Christian America which is militaristic abroad and punitive at home has escaped her. And how, one wonders, does she explain Tony Blair's militaristic-flavoured Christian zeal? The reality is that the main body of the Christian Church (as opposed to the gospels, some sects and courageous individuals such as Williams's mother, Vera Brittain) has never offered a principled opposition to state violence. God and Caesar will strike the neoconservative hawks of the current US administration as a typical production of "old Europe", secularising God and denaturing Caesar.
I have picked out what seem to me to be weak points and failed to do justice to the pages of interesting argument and good sense on such issues as globalisation, peace and war, and the role of women in politics. For my taste, Williams is too fond of appreciative adjectives. And a hobgoblin must have been guiding her pen when she wrote of Bill Clinton: "Undisciplined and promiscuous he may be, but there is a massive engine of warmth in the man."
Lord Skidelsky is professor of political economy at Warwick University