Christianity is not just hanging in there; it's showing increasing vitality says Robert Wuthnow, Professor of Sociology at Princeton University and a Presbyterian.

He was one of the keynote speakers at an international conference on Christianity in the West in Dunedin late last year, hosted by the University of Otago's Liberal Arts school. Professor Wuthnow's paper on secularisation and the future of Christianity offered encouragement to those who feared it was doomed.

"For all of the squabbles, there's a lot of vitality in the Presbyterian Church in the United States, and it's also true of Methodists, Anglicans and Lutherans," Professor Wuthnow said.

At the conference he used the American experience to demonstrate stability in church attendance, look at what could be learned about the future of Christianity and whether it was likely to be changed by social circumstances influencing it.

"It seems to me the big challenge is to figure out why be Christians at all," Professor Wuthnow said.

"It's a practical challenge for people who want to be true to their Christian faith but also want to be able to embrace other concepts.

"It seems to me that Christianity will be increasingly exposed to other religions and to questions about their validity as immigration and mass communication increase."

It had always been exposed to such influences but probably never before at such a popular level. An example of the influence of the mass media was the "what car would Jesus drive?" debate.

"The churches have been very active in environmental issues for the past 30 years but since the religious right belatedly discovered an environmental conscience, the mass media, which ignored what mainstream churches said, started reporting on the matter and the issue is now seen as one [belonging to] the religious right," Professor Wuthnow said.

For Americans, the intertwining of religion and politics ­ despite no state church - had thrown up some unique issues.

"There's been such a close connection between Christianity and politics in the United States that people in the US have a great deal of difficulty in sorting out the difference between Christianity and patriotism."

As American foreign policy had become "more strident and more bellicose", the confusion had extended beyond North America and members of other religions had felt threatened. "So they're reacting against it."

There were global issues for churches - such as the Presbyterian, Anglican and Catholic denominations ­ to consider in tandem with political issues.

"The churches, especially those with global [structures], have a real responsibility to think closely about their own commitments and responsibilities and, since we [Presbyterians] are a global church, we need to listen to our members in South-east Asia, Africa, Australia, New Zealand," Professor Wuthnow said.