Last night in my Christian Traditions class we covered theological liberalism in American Protestantism and its entrance into the scene in the late 1800s and early 1900s. The reality is that the basic differences among churches is not the denominational labels, confusing enough to those just making their way into the church. The one underlying distinction among them all is orthodox or liberal. Students who are not churched find this surprising and not altogether intuitive. They naturally assume a church would be by definition orthodox/supernaturalistic.
If you want a great picture of how liberalism in American Protestantism got a foothold, go to Episode 4, “A New Light” in the series “God in America.” The last half of that episode is particularly illuminating, culminating in the standoff between the Fundamentalists and liberalism in the Monkey trials in Dayton, TN. Along with this video you might want to read J Gresham Machen’s Liberalism. In it he essentially says that liberalism is not a brand of Christianity. It is another religion entirely. You can download the book from the internet for free. Have read it several times and it always instructs and focuses me again on the nature of the theological war in which the church is engaged. And it is a war. Go here for Machen’s book.