conflict vs tug of war

conflict

noun
  • A clash or disagreement, often violent, between two or more opposing groups or individuals. 

  • An incompatibility, as of two things that cannot be simultaneously fulfilled. 

verb
  • To overlap (with), as in a schedule. 

  • To be at odds (with); to disagree or be incompatible 

tug of war

noun
  • A dispute between two parties, particularly an entrenched, back-and-forth dispute. 

  • A game or competition in which two teams pull or tug on opposite ends of a rope trying to force the other team over the line which initially marked the middle between the two teams. 

How often have the words conflict and tug of war occurred in a corpus of books? (source: Google Ngram Viewer )