I never meet a church that wishes they didn't do it. I never meet a leader that wishes they didn't do it. They will all say, to the person, it's hard. It's difficult. It comes with complexities and confusion as you're trying to go across cultures, and you don't understand, you didn't mean to offend somebody but you've offended somebody. But they will all say it just does something.

We do not have an American culture. We have a white American culture and a black American culture. So when those two groups try to get together, [it's] very difficult because they each feel like they have the right to their culture.

I meet almost no one that goes to an African-American church or thinks, "I'm going to do that." Now there are whites in African-American churches. They're interracially married. They're highly committed. Maybe there's a professor or two, or a student.

What happens is sometimes these congregations will still have the white style of worship, even though they're mixed, because folks are willing to give up whatever they may have come with. So it's still quite a stretch for African Americans, yeah.

So we didn't get the denominations and the separate congregations really till about into Civil War time. What's happened then, of course, is now that we've had well over 100 years of this history to establish separate cultures, different ways of worshipping, and different ways of understanding theology so that when people try to come together makes it very difficult. And then, of course, social networks, you know, how do we find a place to worship?

We studied a mosque, and this is when we were at Notre Dame, and in this mosque they had people from a variety of countries, most of them immigrants. In some of the countries, when you go into a mosque you remove your shoes. To not do so could be punishable even by death in that nation. In other countries, it would be a great offense to remove their shoes when they come into the mosque, a sign of disrespect.

I spent a lot of time developing in books why worshipping separately actually impacts inequality, economic, social, on and on. So I really do believe there are huge advantages to being together even though it's difficult, even though we have a lot to learn.