internal affairs vs political science

internal affairs

noun
  • A division of a law enforcement agency investigating incidents and plausible suspicions of lawbreaking and professional misconduct attributed to officers on the force. 

political science

noun
  • The analytical study of public policy and policies, past, present, and prospective. 

  • The systematic study of government and politics. 

How often have the words internal affairs and political science occurred in a corpus of books? (source: Google Ngram Viewer )