By BBC News Online's Peter Gould in Rome (April 1, 2002)
There can hardly be a more difficult time to be trying to promote world peace.
Six months after the attacks on America, the shock waves are still being felt around the globe.
America's "war against terrorism" has seen air strikes on Afghanistan, and there is speculation that the campaign could soon be extended to Iraq.
And as Christian leaders try to preach the Easter message, the Holy Land is in turmoil, with death and bloodshed almost a daily occurrence.
Watching it all from his office at the Vatican, Francois Van Thuan could be forgiven if he felt a little depressed.
He is the president of the Pontifical Council for Justice and Peace, which makes him the Pope's expert on conflicts around the world.
Sitting in his library, we are surrounded from floor to ceiling by shelves of documents and books on some of the world's most intractable problems.
If your mission is to promote tolerance and harmony, it is tempting to ask just where to begin. But the cardinal remains hopeful despite the daily news reports.
"We believe and trust in young people, because they are thirsty for peace and friendship," he says.
"I have experienced this because I have been to many countries, and have spoken with many young people. I love them and trust in them."
Challenges for peace
"September 11 has been a calamity, a tragedy," he says.
"It is a big challenge and we must continue, like in Jerusalem. All nations, America included, must continue to help the dialogue.
If you educate people to war, to fundamentalism, these things will continue
Cardinal Van Thuan
"It is the only way to have peace, to arrive centrally at a point of forgiveness, and after that reconciliation. If we do not have true reconciliation through forgiveness, we will never end war."
So the Vatican insists there can be no peace without justice, and no justice without forgiveness.
But while religious leaders may be speaking the same language, how do they get that message across to those engaged in conflict on the streets?
"If you educate people to war, to fundamentalism, these things will continue. The responsibility of the politicians is to educate the people of their state to peace.
"They are not doing enough."
The cardinal says the media should provide more positive images, rather than just telling young people about fundamentalism, suicide and war.
"Sometimes I think when you show arms and assassination, young people go to school with guns and kill their friends," he says.
"I think we can show more solidarity, more friendship. We can show the positive work of people who went to Afghanistan to help. So many people there are doing positive things, but we speak only about war."
The cardinal is a gentle, quietly spoken man, much admired within the church for his spirituality. He has a quality of holiness that impresses those who meet him.
His commitment to peace and religious tolerance is founded on his experiences in Vietnam, where he was imprisoned by the Communist regime for 13 years.
In solitary confinement, he secretly carved a crucifix from a piece of wood. It now hangs around his neck, from a chain he made from a length of electrical wiring.
Some of his guards discovered what he was doing, but were so impressed by their prisoner and his devotion to his faith that they turned a blind eye.
"They became my accomplices," he recalls with a smile.
"My role here is the promotion of justice and peace in the world, and of course this is something special for me because I am from a country which suffered many years of war.
"I like to promote, with all my heart, justice in the world."
As a member of the Church's elite body of cardinals, Francois Van Thuan will one day be called on to help elect the successor to John Paul II.
Nobody at the Vatican talks about the papal succession, but the cardinal from Vietnam is clear about the role of the Church in the 21st Century, whoever becomes pope.
"Some people said that in the year 2000 we would have peace everywhere," he says
"But there is still war and more conflict. So now we are busy producing a document that speaks about drugs, discrimination, war, weapons production and the threat of arms."
But if the Church has a social agenda, is there not a risk that it will find itself in conflict with the state?
"The Church has no interest in conflict with the state because we have no army, no land, we have no money. There is no conflict. But the church speaks and promotes justice and peace.
"If a country is manipulating its power for war, for injustice, you might think it is a conflict, because the darkness and the light are in opposition. If we show the light, it is no good for the darkness.
"We hope we can help society change and have more peaceful times, more love and more prosperity."