Inevitably, parts of Niebuhr date: his harping on the self-evident virtues "liberalism" are bound to ring a false note in the ears of those who have lived beyond Niebuhr's time and situation (see Jonathan Zasloff's perceptive review). But it is worth using one's sense of history to recall that in context, Niebuhr's clarity of vision took a particular kind of persistence, and of courage. Caught in in the cross-torrents between Communism and anti-Communism, it took stamina not to be swept into the vortex. Indeed, I think this insight may lead us to the ultimate irony. Specifically, I'd venture that it is precisely the Niebuhrian posture of principled skepticism that drives evangelicals so wild about what we used to call "mainstream" Christianity: his skepticism comes across as a lack of faith or a lack of moral certainty. Seen rightly, I doubt that there have been many more certain than Niebuhr as to where he should stand, should try to stand. And to see himself thus as the progenitor of the new Christian triumphalism--I suspect that Niebuhr would be not at all indifferent to what I think he would regard as a major calamity for his faith. At the same time, I suspect he might be able to understand it as a good (if bitter) joke.
Anyway, a good occasion to quote the one bit of Niebuhr that the incurious are most likely to recognize and remember:
Grant us grace our Father, to do our work this day as workmen who need not be ashamed. Give us the spirit of diligence and honest enquiry in our quest for the truth, the spirit of charity in all our dealings with our fellows, and the spirit of gaiety, courage and a quiet mind in facing all tasks and responsibilities.