It is the birthday of America's greatest 20th Century theologian. He was our "public theologian," a man consulted by the powerful and whose thought remains influential. Barack Obama quotes him as does Krista Tippett. In fact, he is a favorite of politicos from left to right. This despite his having died in 1971 (I was 13 at the time).
Michael Westmoreland-White has provided a very fitting memorial to Niebuhr -- although Michael doesn't share all of Niebuhr's views (Michael is a committed pacisfist).
For further information and links check out the Niebuhr Society page.