clarion call vs polemic

clarion call

noun
  • Appeal, urgent call to action. 

polemic

noun
  • An argument or controversy. 

  • A strong verbal or written attack on someone or something. 

  • A person who writes in support of one opinion, doctrine, or system, in opposition to another; one skilled in polemics; a controversialist; a disputant. 

adj
  • Having the characteristics of a polemic. 

How often have the words clarion call and polemic occurred in a corpus of books? (source: Google Ngram Viewer )