Liberal Christianity or Theological Modernism is a broad term which basically refers to a movement within American Protestant denominations to stress the social role of Christianity, as in the Social Gospel of the early 20th century. This movement is characterized by a lack of emphasis on or denial of the plenary Divine inspiration and authority of the Bible, and commitment to doctrinal purity. Prevalent Biblical themes such as repentance from personal moral sin, hell and damnation for those who reject Christ, His blood atonement and His future literal reign are minimized, or militated against. In 1937, H. Richard Niebuhr summarized their basic gospel message as preaching that "A God without wrath brought men without sin into a kingdom without judgment through the ministrations of a Christ without a Cross."
Theologically, Liberal Christianity stresses a basic continuity between man and God, emphasizing the immanence of God rather than His transcendence. It tends to see religious knowledge emerging from research and the use of reason, as superior to Biblical revelation. Thus the liberal idea of religion as a personal relationship with God is one which is not necessarily bound to a Biblical doctrinal basis. This stand sin in contrast to salvation resulting from faith in the Biblically substantiated gospel of grace, and in conformity with orthodox theological beliefs.
Origins of liberal Christianity
Schleiermacher emphasized that religion was a personal relationship with God, and downplayed historical Christian doctrines such as the doctrine of creation, doctrine of Incarnation, doctrine of eternal life, etc.
Schleiermacher sought to re-establish the importance of Christianity using Christian religious experience rather than scientific knowledge. Ritschl revised Schleirmacher's idea and tried to re-establish their authority using Kant's idea of moral experience and in the fulfillment of the Kingdom of God. 
Doctrines that did not relate well to religious experience or moral experience tended to disappear.
Role of the Bible
Liberals view the Bible as the witness of God rather than the word of God. Strangely the view looks for support by a type of literal interpretation - though this should not be confused with the form of Biblical literalism found in fundamentalist and conservative churches - of the words of Paul in his second letter to Timothy:
All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness,... 2_Timothy 3:16
Here some see Paul conveying that that scripture is a direct result of the authors contact with God ("witness"), whilst stopping short of claiming actual divine authorship ("word"). Conservative Christians would answer that Paul states here that the words which make up scripture are God-breathed, and that the Bible records God's promise to preserve His words, not merely His ideas.
As a result Liberal Theologians view the Bible as a text to be interpreted in its historical context but through liberal critical analysis. As a result, many hold that texts such as Genesis’ early chapters or Old Testament miracles are poetry or fables - having a message, but not to be taken literally (in spite of thew New Testament referring to such as literal events). This approach began to dominate most Protestant denominations in the early 1900's, and was challenged by Neo Orthodoxy and Fundamentalism after 1940. Examples today include some churches within Anglican/Episcopalian, Lutheran, Methodist, Presbyterian, and United Church of Christ churches. The word "liberal" in liberal Christianity does not refer to any political agenda or set of beliefs, although liberal theological beliefs will often form the basis of liberal political beliefs.
In addition, liberal Christians are seen taking an unwarranted pick-and-choose approach to the Bible, declaring that passages which they favor were intended by God to be followed today, while other parts are outdated or need to be reinterpreted, in order to conform with current trends. As needed, the spirit of the Bible is emphasized in such a way that its specific wording can be ignored or negated. As Machen comments,
Admitting that scientific objections may arise against the particularities of the Christian religion-- against the Christian doctrines of the person of Christ, and of redemption through His death and resurrection--the liberal theologian seeks to rescue certain of the general principles of religion, of which these particularities are thought to be mere temporary symbols, and these general principles he regards as constituting "the essence of Christianity.
Rather than the Bible being wholly inspired by God, many liberal Christians believe that the Bible was the work of numerous editorial redactors - homophobic ones in cases where pro-homosexual writers wish to see homoeroticism positively portrayed between Bible characters - or even that certain parts of the Bible that do not agree with liberal theology are later additions that do not belong in the Bible at all. In extreme cases, some liberal Christians even engage in politically correct censorship against those who quote Bible verses that tend to disprove a liberal Christian position. It may also esteem other books as works of God as well as the Bible.
Most of those within mainline denominations evidence beliefs and its effects which are at variance with Biblically based historical Christian faith. Two issues usually indicative of liberal denominations are support for abortion and homosexuality. For a more detailed treatment, see Homosexuality and Christianity.
Economic and historical aspects
In terms of economics, liberal Christianity emphasizes Testament eschatology towards the Kingdom of God into the liberal "law of progress." History does indeed show a growing maturity in technology, thought, and social relations, but conservatives argue there is nothing within the forces of history to suggest that good will triumph over evil. Conservatives say liberals deemphasize sin, i.e. evil triumphing over good.
The Liberal Christian scholar Edgar S. Brightman said, "I believe in God because I believe that history represents a steady, moral progress." This was turned around by the neo-orthodox scholar Langdon Gilkey when he stated "I believe in God because to me history precisely does not represent such a progress."
Liberal Christianity's Anti-Zionism
Strong elements in liberal Christianity have opposed Zionism since 1920, while at the same time combating intolerance and social hostility toward Jews inside the United States. Support for Zionism is a core belief of Fundamentaliam.
In American Protestantism and a Jewish State (1973) an Israeli government official Hertzel Fishman analyzed several years (1937-1967) worth of Christian Century and concluded that the magazine consistently and historically opposed a Jewish State in Palestine, obstructed immigration of Jewish refugees, minimized the Holocaust, tried to reduce Israel's boundaries and supported Arab 'rights'." Although Dr. Fishman found instances of the magazine denouncing individual acts of anti-semitism, he found that the magazine was consistent in its intolerance and opposition to collective acts of a Jewish "peoplehood."
Neo-Orthodoxy opposes Liberalism
The first-quarter 20th century neo-orthodoxy movement was a renewal of Christian doctrines that had been neglected by liberal Christianity within the American and European academy. At the heart of the neo-orthodox renewal appeals to symbolic and aesthetic interpretations of long forgotten Christian doctrines can be found in the works of Karl Barth, the Niebuhr brothers, and Paul Tillich.
- Ahlstrom, Sydney E. A Religious History of the American People. (1972), the standard scholarly history. Excerpt and text search
- Luker, Ralph E. "Liberal Theology and Social Conservatism: a Southern Tradition, 1840-1920." Church History v 10#2 1981. pp 193-207 p online edition
- Marty, Martin E. Modern American Religion, Vol. 1: The Irony of It All, 1893-1919 (1986); Modern American Religion. Vol. 2: The Noise of Conflict, 1919-1941 (1991)
- Noll, Mark. A History of Christianity in the United States and Canada (1992), by a conservative historian. Excerpt and text search
- Machen, J. Gresham (1881-1937), Presbyterian theologian. Christianity and Liberalism (1923). Online edition
- M. James Sawyer, Liberalism. Web page
- The Kingdom of God in America (1937), New York: Harper and Row, 1959, p. 193
- Langdon Gilkey, Naming the Whirlwind: The Renewal of God-Language, (1969), 73, 74, and 75
- God's promise to preserve His Word
- All Scripture Is Given By Inspiration
- What Liberal Protestants Believe Beliefnet. Accessed 15 March 2008
- J. Gresham Machen, Christianity and Liberalism; Introduction
- Documentary Hypothesis
- Is it true that 1 John 5:7...?
- Revealing Statistics: Differences Between Denominations
- Basic idea for this paragraph is from April 26, 1939 The Christian Century, Reinhold Niebuhr, "Ten Years That Shook My World", pages 542-546
- Washingtonpost Obit of Langdon Gilkey
- [http://books.google.com/books?id=-BPjHQAACAAJ David A. Rausch, Zionism Within Early American Fundamentalism 1878-1918: A Convergence of Two Traditions (1979) pp 23-25