Reinhold Niebuhr (1892–1971), born in Wright City, Missouri was a major American theologian and political thinker of the mid-twentieth century. A graduate of Yale Divinity School, Niebuhr served as pastor of Bethel Evangelical Church in Detroit (1915–28), where he became deeply interested in social problems. In 1928 he began teaching at Union Theological Seminary, becoming professor of applied Christianity in 1930; he remained in this post until his retirement in 1960.
"In the early 1930s he shed his liberal Protestant hopes for the church’s moral rule of society and became a political activist and a Socialist. A prolific writer, he urged -- notably in Moral Man and Immoral Society (1932), Christianity and Power Politics (1940), and The Nature and Destiny of Man (2 vol., 1941–43) -- clerical interest in social reforms as well as the beliefs that men are sinners, that society is ruled by self-interest, and that history is characterized by irony, not progress.
"After World War II, he dropped much of his social radicalism and preached 'conservative realism.' In his later works, such as Faith and History (1949), Niebuhr argued for balances of interests and defended Christianity as the world view that best explains the heights and barbarisms of human behavior. In A Nation So Conceived (1963) he analyzed aspects of the American character. He also wrote Man’s Nature and his Communities (1965), Faith and Politics (ed. by R. H. Stone 1968), and The Democratic Experience (with P. E. Sigmund, 1969)." (from The Columbia Encyclopedia, Sixth Edition)