cause célèbre vs hot potato

cause célèbre

noun
  • An issue or incident (originally, a legal case) arousing widespread controversy or public debate. 

hot potato

noun
  • An awkward or delicate problem with which nobody wants to be associated. 

  • A child's game in which players pass a ball or other item between them, with the object of avoiding being left holding the item when time expires. 

How often have the words cause célèbre and hot potato occurred in a corpus of books? (source: Google Ngram Viewer )