If you see the advertising from my local Episcopal denomination here in New Mexico, you would think that they were Assemblies of God. They're very evangelical, and it turns out that their churches are full, even in a denomination in extreme decline. So the fact is: it is reversible.

What if you went to a baseball game, and nobody brought a ball? The players just stir around for two hours. I don't think you'd go back, would you? Likewise, when you go to church, but the minister doesn't bother to hold church because he wants to talk about Medicare or something, why go back? Well, people don't.

There are always nonsense excuses that are offered on behalf of the declining denominations. "It wasn't that people left; it's lack of fertility within the congregations." No, there's a lack of fertility only because these congregations are very old. The sons and daughters of the current members left and took their fertility with them. That's why there's no fertility in these denominations, because the average age is 65. That's the way organizations die. The young leave.

So what will happen next? Will the mainline denominations eventually decide to shut down shop?

One fellow from the United Church of Christ -- which used to be the Congregationalists -- bragged to me, "It doesn't really matter what the members do. We have endowments that we can live on forever." Well, that's an interesting attitude, but it won't work. They will close down. Many have been living off their real estate for years; they close a church and cash in the property. But in this American market, denominations that cannot bring in new members and support will eventually close. That's the way it is.

My old hometown is a perfect model of what the American religious market is like. When I was a kid, Jamestown, North Dakota was split about 60 percent Protestant and 40 percent Catholic. The Protestants came in about seven varieties of Lutheran, and the biggest church was the Methodist and the second biggest was the Presbyterian. They're big churches and they stood on the corner of two downtown blocks, two churches facing one another. The Assemblies of God met in an apartment above an auto parts store. The Church of the Nazarene met in what had been a little one-room country schoolhouse that had been moved into town and had a steeple attached to it.

If you go to Jamestown today, the Nazarenes could not even fit their choir into what was their church when I was a kid. The Methodist and the Presbyterian churches are still sitting there on their corners and staring across the street at one another -- but they're empty, except for some very elderly people. The Assemblies of God has got a great big church building on the edge of town, they have two full-time ministers, and they're the biggest church of town.

What happened? Well, the sons and daughters of the people who used to go to the Methodist and Presbyterian churches left, and they went to the Nazarenes and to the Assemblies of God. There's just as much religion in Jamestown now, if not more, than when I was a kid. But who practices and who supplies it has changed radically. I could never have anticipated that when I left for college. I could never have anticipated it -- but it happened, and it happened that way all over the country.

As a matter of fact, one of the big changes is that the second-largest Protestant body in the United States today, second only to the Southern Baptists, is made up of the non-denominational evangelical Protestant churches. They hardly existed forty years ago, but today they probably have half as many members as the Southern Baptists. That's real growth, and it shows that the product matters. People in evangelical churches witness to their faith and bring their friends and neighbors to church, and the people in liberal churches -- at least according to survey data -- don't witness and don't invite anybody into their church. It makes a great deal of difference.