JUDY WOODRUFF:

Robert Jones, welcome to the program.

So, provocative title, "The End of White Christian America." But you say in the book what you're really asking is why white Protestant America has experienced such a dramatic decline.

Why did you want to tackle that question?

ROBERT JONES, Author, "The End of White Christian America": Well, thanks for having me.

You know, when I was looking at the data, I realized that we had really crossed this very significant threshold in American culture. And that is that we had moved, just in the last eight years, from being a majority white Christian country, 54 percent in 2008, when Barack Obama was running for president the first time, to being a minority white Christian country.

Today, we are 45 percent white and Christian. Now, when I use the term white Christian America, I am really referring to this cultural and institutional world built primarily by Protestants. So, if you think about the cultural center of the U.S. being a kind of Waspy, white, Anglo-Saxon, Protestant culture, that's the culture that I'm talking about and that has really faded from the center of American culture.