I heard Linda Ronstadt remembering Kate on CBC's As It Happens this afternoon. She told a story of sitting at a table with John Rockwell, the NYT music critic, when the McGarrigle sisters sang this song. She said she looked over and there Rockwell was, weeping. Once he composed himself he told Ronstadt the song always did that to him. She admitted it took her forever to be able to perform it herself, because she was affected the same way. She finally did cover it on her Get Closer album in 1982.