You're not blind to ways in which American missionary efforts might have been culturally insensitive, even imperialistic, but you also see some real positives as well. Can you explain why you find that understanding the patterns of American Christianity, especially in its frontier period, as helpful for understanding what is happening around the world today?

The insights in the book, to the extent that they are valid, owe a tremendous amount to the work of Andrew Walls. Andrew Walls has pointed out that worldwide Christian expansion was prompted by the voluntary organization of religious groups, first Catholic and then Protestant, and the separation from the European pattern of "Christendom," in which there was a tight interweaving of political power and the churches. In most of the places of the world today where Christianity is advancing, there is not that Christendom history.

So in China, the government is either opposed or indifferent to Christianity, and Christian churches are growing by voluntary organization or voluntary outreach. That is the pattern that began to be important in the world with the United States in the latter part of the 18th century and the 19th century.

I actually think there are important connections between the western and non-western world, some good and some bad, but it's been true everywhere in world history that people become Christians when they themselves want to. The agency of non-westerners is the key matter, which comes more clearly into focus today when you realize that most of the world does not exist in the European situation where there were these kinds of "Christendom" connections between churches and government. 

What made America's missionary efforts so effective at spreading churches around the world? And are those qualities, that made American missionary efforts effective, still in evidence today? Or are we departing from those qualities?

I'm not one hundred percent sure that American missionary efforts were ever all that successful. What they did display was a form of organization that eventually became successful. So it was ad hoc voluntary organizations that mobilized American missionaries, and today it's ad hoc voluntary organizations that mobilize the spread of Christianity in general.

I'm quite sure it's not that Americans are that important. Americans and Northern Europeans were important in planting the seeds of Christianity, but where those seeds flourished had a lot more to do with the quality and character of native groups than it did with the missionaries themselves.

It's becoming harder to hold American Christianity and global Christianity apart, as we have such a spectacular explosion of immigrant churches in the United States today. Are there ways in which immigrant churches in America today are challenging and transforming, even educating non-immigrant churches in the United States?

The newer Christian churches that draw tremendous strength from immigrant populations show adaptability in the face often of serious difficulty, a community-building quality, and trust in the immediate power of God to be at work in local situations. These are not just things taking place in the United States, but they have existed wherever there have been newer Christian movements. They certainly existed in the United States in the 18th and 19th centuries.