assertion vs nullification

assertion

noun
  • A statement in a program asserting a condition expected to be true at a particular point, used in debugging. 

  • A statement or declaration which lacks support or evidence. 

  • The act of asserting; positive declaration or averment. 

  • Maintenance; vindication 

  • Something which is asserted; a declaration; a statement asserted. 

nullification

noun
  • The nullification crisis in U.S. history, confrontation between the state of South Carolina and the federal government in 1832–33 over the former's attempt to declare null and void within the state the federal Tariffs of 1828 and 1832. 

  • Surgical removal of genitals (and sometimes nipples) as a form of body modification; a person who has undergone this surgery is a nullo. 

  • The act of nullifying; a rendering void and of no effect, or no legal effect. 

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