Liberal Christianity is not any one denomination, though it tends to be identified more closely with mainline Protestantism, what used to be called “The Seven Sisters” of Methodist, Episcopal, United Church of Christ, Presbyterian, Evangelical Lutheran (as opposed to Missouri Synod Lutheran), American Baptist (as opposed to Southern Baptist), and Disciples of Christ. Liberal Christianity however can be found in pretty much any denomination.
I call Liberal Christianity dominant because it in fact dominates Christian institutions in America. Private, church affiliated universities and hospitals are almost exclusively of the Liberal Christian variety. Church hierarchies are generally quite liberal. Liberal Christian views are routinely championed in the press. Liberal Christianity is generally supportive of government power and government bureaucracy even if it might quibble as to how that power is applied.
Liberal Christianity does not refer to people who are politically liberal but otherwise believe the same things as more conservative Christians. A political liberal who believes in, say, the Virgin Birth, the Inerrancy of Scripture, or Papal Infallibility, is not a Liberal Christian.
Liberal Christianity takes a minimalist approach to doctrine and personal morality, and puts a major emphasis on social moral causes, whatever they may be.
The curious thing about Liberal Christianity is that it is always claiming to be a fresh, new and improved version of Christianity, when in fact it is a few hundred years old.
Every few years we read about “a new generation of American Evangelicals” questioning dogmas like Biblical Inerrancy, or some Biblical moral teaching. Both the “new generation” and the journalists reporting about them are ignorant of the fact that every single generation of American Evangelicals dating back to colonial times has posed exactly the same questions.
What is the source of this ignorance? Why is it that they can’t recognize that they are not doing anything new, but in fact repeating an old pattern?
It is because Liberal Christianity, though dominant on an institutional level and invariably popular with the press, always fails to perpetuate itself on the grassroots level. Conservative Christians will often have Liberal Christian children. Liberal Christians will usually have agnostic children, because the children will figure out the fatal flaw of Liberal Christianity:
If the whole point of being Christian is to be a Good Liberal, then why be Christian?
Since Liberal Christianity can only perpetuate itself through conversions from Conservative Christianity, it considers itself as being always new. It has no cultural memory.