THE PAPACY is the oldest and most successful institution in the world. Asking the Pope to abandon or water down Catholic doctrine would be like asking him to abolish his own office. Joseph Ratzinger has been the most powerful figure in the Church after John Paul II for the past two decades. It is entirely right that he should have the opportunity to serve the Church in the capacity for which he is so obviously head and shoulders above the rest. Among so many eminences, he was pre-eminent.

As usual, the BBC got the story all wrong. The task for the new Pope is not to take sides between liberals and conservatives. Nor was that the choice the cardinals faced in this extraordinarily rapid conclave. All cardinals are, by definition, conservative.

No, the great issue for Pope Benedict XVI is the one that he set out in his remarkable sermon at the preconclave Mass in St Peter’s. Does he wish to lead the Church down the primrose path of secularism, following the Christian heartlands of Europe in their descent into moral relativism, or does he intend to turn towards the new missionary Church of Latin America, Africa and Asia, to reaffirm the faith of Christ, the faith of St Peter, the faith of John Paul II? That is the real choice.

What the fight against communism was for John Paul II, the fight against rampant secularism will be for Benedict XVI. And all those anti-papist commentators who protested at the attention given to John Paul II’s illness, death and funeral will be gnashing their teeth once battle commences.

I believe, and firmly, that with God’s help Benedict XVI has it in him to be another great pope. He will build on the foundations laid by John Paul II, whose saintly genius he understood better than anybody else. And he knows exactly how to galvanise not only the devout, but also the vast dormant pool of lapsed Catholic laity.

Pope Ratzinger will be even more controversial than his predecessor. He began life under the Weimar Republic, which collapsed because it took moral relativism to extremes and succumbed to the secular ideologies of Left and Right.

He grew up under the Third Reich, witnessing at first hand the coercive and corrosive effects of a political religion. Though his father was no Nazi, Joseph was obliged to join the Hitler Youth and was fortunate to avoid military service. Far from this experience being an obstacle to his elevation, it was this dark night of the soul that qualifies him for it.

Joseph Ratzinger is virtually the first German since 1945 to hold any high-profile international office. Hostility to his nationality is widespread: he has been caricatured as “God’s rottweiler” and the “Panzerkardinal”. But his elevation is not only good for Christendom but also for Germans.

The revelation of the diabolical nature of the Nazi system, above all the murder of the Jews, confirmed in him the determination to devote his life to God. This was his form of atonement, and he has accompanied John Paul II on the spiritual journey that brought about the reconciliation of the Church and the Jewish people that was one of the greatest achievements of the past pontificate.

We cannot expect this Pope, of all popes, to abandon the “deposit of faith” which it is his sacred duty to preserve. There will be no change on issues such as contraception or the ordination of women, no legitimisation of gay marriage, no slackening in the determination to protect the unborn child or to stop the destruction of human embryos by scientists. The Nazi experience has taught Benedict XVI the dangers of eugenics and euthanasia, and we can expect an even more vigorous crusade against these evils.

Where I do expect movement during the Ratzinger pontificate is on ecumenical relations with the Orthodox and perhaps also Protestant churches. The last Pope opened up this Pandora’s box, bringing several of the smaller Eastern churches back into the Catholic fold. If the battle against the intolerance of secularism is to be won, Benedict XVI will have to find a way of reaching out to his fellow Christians to make common cause.

The last Pope was rarely given credit for his radical new ways of interpreting ancient doctrines, and the cardinals evidently realised that only Joseph Ratzinger had the learning and intellect to explain these exciting ideas not only to the laity but to the clergy too. In particular, the Theology of the Body, which sees sexuality as an emanation of divine love, has enormous unrealised potential to enthuse the young.

As Prefect of the Congregation for the Doctine of the Faith (the Holy Office) since 1981, Ratzinger has been treated as a kind of grand inquisitor by the media. This is based on the “persecution” of a handful of theologians, most famously Hans Küng. In reality, this persecution amounted to a change of job title: Küng could no longer call himself a professor of Catholic theology, but continued to teach exactly the same things at the same university.

I once discussed Ratzinger with Küng, his Swiss contemporary and arch-rival. While admitting that the new Pope was a clever man, Küng insisted that he had done great damage to the Church. But Küng believes that all the great world religions essentially teach the same, which is manifestly incompatible with Catholic doctrine. I came away with the impression that of these two brilliant theologians, it was Küng who had succumbed to the temptation to think he knew better, while Ratzinger had submitted to the authority of the Church. Ratzinger is no inquisitor, but Küng is a heretic.

And so when he described himself on the balcony yesterday as “a simple and humble worker in the Lord’s vineyard”, there was no false modesty.

That is how he sees himself. And given his precarious state of health, he would gladly have accepted another candidate. But there was nobody else up to the job.

Join the Debate
Send your e-mails to debate@thetimes.co.uk

Times Recommends

• In the real world, the public sector must pay
• Playing politics in a land of double Dutch
• Be like the plinth people: not set in stone