Rahm Emmanuel evidently used the word "retarded" at a strategy meeting in 2009. It's really not appropriate but people often blurt out stupid things that they later regret. What's interesting to me is Slate's take on this "scandal."
Slate has run an article that explores the clinical usage of the word "retarded" and also references it's usage hard news stories to that term. Whatever Rahm's intent I can guarantee you that he wasn't using the word retarded in a clinical sense, nor was he hoping to convey to readers a factually accurate clinical diagnosis. He meant it as a pejorative and no matter what the clinical diagnosis is or was it's use as a pejorative has never been appropriate. Like I said, I don't think it's a huge issue but Slate's framing of this issue in terms the current clinical nomenclature is bizarre.