Today's OED antedating: "bleeding heart"

Bleeding heart, slang, pejorative, political naïf with more empathy than sense ("bleeding," ppl. a., sec 5 (b), first use cited 1958): Book titled Back Home, by Bill Mauldin, 1947, ch x, p 192: "The people who belong to the current anti-immigration faction love to refer sardonically to the opposition as bleeding hearts and do-gooders and pipe-dreamers, and on most of us I guess they can make the rap stick."