Slacktivist, a blogger who is best known for his incredibly extended review of the Left Behind series of novels (brief recap: They're horrible), invokes Niebuhr in response to majoritarian arguments made by religious leaders last week in response to the Obama administration's announcement that they would no longer defend the Defense of Marriage Act in court:
I would also point MacArthur toward good old Reinhold Niebuhr, the great 20th-century theologian of human nature, and particularly to The Children of Light and the Children of Darkness: A Vindication of Democracy and a Critique of its Traditional Defense. There, as throughout all of his thinking, the central idea for Niebuhr is sinful human nature.
The basic idea for Niebuhr is that people are sinful and therefore not to be trusted with unchecked power. Talk of "theocracy" won't do for anyone who accepts this Pauline/Augustinian/Calvinist/Niebuhrian view of human nature. Every theocracy will be run by sinful, prideful, fallible, corruptible humans and sinful, prideful, fallible and corruptible humans cannot be trusted with the power to speak or act on behalf of God. Give a sinful human that kind of unchecked power and you've created a monster. For Niebuhr, unchecked power was an invitation to evil.
Given that belief, and his view of human nature, Niebuhr concludes that something like Madisonian democracy -- government of the people, by the people and for the people, restrained by a bill of rights and with a built-in system of checks and balances -- is the best form of government.