bickering vs tug of war

bickering

noun
  • Petty quarreling. Usually considered a childish behaviour, although often applied to adults. 

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 bickering and tug of war occurred in a corpus of books? (source: Google Ngram Viewer )