hot potato vs impasse

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. 

impasse

noun
  • A deadlock or stalemate situation in which no progress can be made. 

  • A road with no exit; a cul-de-sac. 

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