James Comey has confirmed that he's the man who's been calling himself Reinhold Niebuhr on Twitter. David Bromwich wrote about Niebuhr (1892-1971) and his book The Irony of American History in the LRB in 2008:

Irony can turn into tragedy, and Niebuhr addressed that possibility in the last sentence of his book: ‘If we should perish, the ruthlessness of the foe would be only the secondary cause of the disaster. The primary cause would be that the strength of a giant nation was directed by eyes too blind to see all the hazards of the struggle; and the blindness would be induced not by some accident of nature or history but by hatred and vainglory.’