"Religion is responsibility...."

Interestingly, the poets had already come to Niebuhr's conclusion, albeit on a very different basis.

Moral Man and Immoral Society challenged religious idealism with political realism. Change, if it happens, will happen because those who are oppressed figure out how to get and use power. If change isn't happening, we should seek the causes in the interests of the powerful. And once change does happen, we should not expect the golden age of peace and justice, but a repetition of the cycle, with a different set of people in the seats of the powerful.

That was not how Christians expected change to happen. Protestant Christians in 1932 still put tremendous faith in the power of right-minded individuals to change their society. Compared to moral ideals, law and power played relatively minor roles in securing justice. If poverty, ignorance, and racial hatred were not disappearing as quickly as people of good will might expect, that was largely because the people of good will did not yet know enough sociology to put their ideals into practice. Walter Rauschenbusch had put it this way: "If the twentieth century could do for us in the control of social forces what the nineteenth did for us in the control of natural forces, our grandchildren would live in a society that would be justified in regarding our present social life as semi-barbarous."

Eliot's wasteland; Yeat's gyres; Pound's theory of usury in history; even Hemingway's clean, well-lighted place and Fitzgerald's boats beating against the current but being borne ceaselessly back into the past.

Precisely because that Social Gospel idealism was based in a particular idea of God and of God's dealings with humanity, it proved remarkably durable. Among middle class Protestants in North America, neither World War I, nor the upsurge of racial violence after the War, nor the beginnings of the Great Depression could dislodge it. But Reinhold Niebuhr did.

It was dislodged by World War I and Spain ("Yesterday all the past") for the poets and writers, and never put back together again (except for Eliot and Auden, who turned to a more durable form of Christianity than they were raised with.  For Auden, Kierkegaard also helped.)  But it was an optimism that proved to be durably American, as Niebuhr would point out in his analysis of American exeptionalism, The Irony of American History.  (And just in passing, I don't agree with Hauerwas, though I'd like to read his critique.  I suspect he wants to put God back in charge so humanity can be God's agent and vice-regent.  I find Niebuhr's analysis if power too trenchant to be dislodged by claiming he's a closet heretic.)  The other irony of modern history, as the author points out, is that Niebuhr became the air we breathe, the water we swim in:  the success of his ideas made him invisible:

For the next several decades, Niebuhr was the one who defined how people with a realistic faith would deal with the world. From Martin Luther King in jail in Birmingham to John Foster Dulles at the State Department, hundreds of people in leadership positions consciously drew guidance and inspiration from Reinhold Niebuhr, and thousands more followed his ideas without knowing exactly where they came from. The result, with an irony that Niebuhr himself might have appreciated, is that the widely shared ideas that make the mature Niebuhr appear to fade into the background of his age are in fact often his own.

Niebuhr remains relevant, no matter how much the world no longer resembles the post-war world he grew old in.  I've heard too many complaints in internet comments about having to use one's vote (regarded as a sacrament, a holy thing which should never be sullied by the impure and the insufficiently ideological) on the "lesser of two evils," as if such a choice is anathema and damning to the individual soul.

"We are responsible for making choices between greater and lesser evils, even when our Christian faith, illuminating the human scene, makes it quite apparent that there is no pure good in history, and probably no pure evil either. The fate of civilizations may depend upon these choices between systems of which some are more, others less just."

Clinton or Trump, in other words.  You don't get to claim purity by writing in a candidate, or refusing to vote at all because none are worthy of your effort.  Nor do you abdicate a citizen's responsibility by refusing to participate.

And I catch a glimpse of how I would critique Hauerwas:

On the one hand, it is pretty clear that the political arena as Christian realism pictures it falls far short of the continuity and coherence that MacIntyre would require for a genuine moral discussion. It even more clearly falls short of the theological unity that Hauerwas demands of Christian ethics. 

Hauerwas and MacIntyre are not wrong to regard ethics as the result of a consensus opinion by a community:  that's the very definition Aristotle gave it when "ethics" in his Greek meant "behavior" in our modern English.  Aristotle's ethics describes no more than the behavior of his fellow Athenians; and his book is more akin to a self-help book than a treatise on the difficulties of being moral.

Aristotle wasn't concerned with being moral.  That was more the concern of Sophocles and Euripides (and to a lesser degree, at least in modern terms, Socrates).  Hauerwas demands a theological unity of Christian ethics, but already I hear a claim for power, for setting the terms of the debate and the boundaries of the discussion that suit Hauerwas, but might well exclude someone else.  Very hard to make the first last and the last first if you first insist on unity, theological or otherwise.  A genuine moral discussion does, I think, require continuity and coherence, but you can't even find that in the history of the children of Abraham they wrote for themselves, their history as the people with a covenant with God.  How do you hope to establish a basis for such a "genuine moral discussion" if that is what history teaches us we can accomplish?  Or, as Niebuhr put it:

"God's order can never be identified with some specific form of social organization," he wrote. It is very important to arrive at concepts of justice which draw upon the common experience of mankind and set a restraint upon human self-interest. But it must be recognized that insofar as such principles of justice are given specific historical meaning, they also become touched by historical contingency."

You can see the bones of modernism poking out of the soil there, ready to raise mountains.