federalism vs unionism

federalism

noun
  • Covenantalism. 

  • A system of national government in which power is divided between a central authority and a number of regions with delimited self-governing authority. 

  • The belief that such a system is superior to other forms of government. 

unionism

noun
  • Support for the North (the Union) during the American Civil War. 

  • Support for the continuance of the United Kingdom (especially with respect to Northern Ireland). 

  • The support of advocacy of a union, especially of a trade union. 

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