Yup, so anti-Communist he came out against the Vietnam War in 1966. http://spot.colorado.edu/~chernus/NonviolenceBook/Niebuhr.htm
Tom Frank blurbed this book. (I read half of it found it too soft on the cold war liberals.) Has much on Neibuhr. Found his book on C.Wright Mills, Paul Goodman and W.A. Williams much sharper.
When America Was Great; The Fighting Faith of Postwar Liberalism by Kevin Mattson
-- Michael Pugliese