According to the theology blog Between Two Worlds, the percentage of people who attend church regularly is not nearly as high as some recent polls suggest:
How many Americans go to church regularly?
If you listen to the answers provided by major opinion research firms, the answer usually hovers around 40%. (National Opinion Research Center: 38%; Institute for Social Research’s World Values: 44%; Barna: 41%; National Election Studies: 40%; Gallup: 41%.)
But in recent years this consensus has been challenged. It seems that it’s more accurate to say that 40% of Americans claim to attend church regularly.
The post goes on to suggest that the actual percentage of regular church goers is closer to 20%.
Assuming that's correct, perhaps the recent resurgence of fundamentalism is really an indication of Christianity's current weakness. Maybe the reason some people are moving towards more extreme forms of Christianity is that they see more liberal churches secularizing themselves out of existence. I've seen that thesis offered elsewhere, but I've always been suspicious of it. In light of the statistics presented in this blog entry, I'll have to reconsider.