legalize vs sanction

legalize

verb
  • To make legal or permit under law. Either by decriminalising something that has been illegal or by specifically permitting it. 

sanction

verb
  • To give official authorization or approval to; to countenance. 

  • To penalize (a state etc.) with sanctions. 

  • To ratify; to make valid. 

noun
  • An approval, by an authority, generally one that makes something valid. 

  • A penalty, punishment, or some coercive measure, intended to ensure compliance; especially one adopted by several nations, or by an international body. 

  • A law, treaty, or contract, or a clause within a law, treaty, or contract, specifying any of the above. 

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