In my book, The Right of the Protestant Left (Palgrave, 2012), I tried to restore Niebuhr to his precarious place within what I called the “old ecumenical Protestant left.” The reality is, the more Niebuhr’s celebrity rose among those outside of the church, the more marginal I found that he became to the main currents of liberal American Protestantism. I’m not referring here to the pacifist circles that Niebuhr turned his prophetic pen on. Rather, his friends, colleagues, and younger brother were so frustrated by Niebuhr’s indifference toward building a inter-Protestant world community—their chief interest—that they even considered leaving him out of their project altogether. Niebuhr was eventually reconciled to the ecumenical movement by his critique of “secularism” and his analyses of national and world problems through the lens of “original sin.” Still, those closest to Niebuhr continued to deride him as the “sackcloth and ashes man,” the “sin-snooping” saint who was fundamentally out of touch with the Christian hope….