[He] lamented that the “exuberant optimism of the first few months of the...administration” had given way “to doubt and drift” in a Washington nearing “the point of paralysis.” The president, [he] wrote, was “a moderate confronted by radical facts,” among them “a whopping budget deficit and an alarming army of the unemployed.” [The president] was in “trouble both with the conservatives who think he has gone too far and the liberals who think he has not gone far enough.”
The answer may surprise you -- but it may not.
UPDATE: Beam me up, Scotty! -- it indeed was James Reston of the New York Times, writing about President John F. Kennedy in 1963, shortly before he was assassinated (Kennedy, not Reston). It's resurrected in an outstanding article about the JFK assassination by Frank Rich in New York magazine (although I'm still not down with that whole lone gunman thing).