leftism vs political theory

leftism and political theory both are nouns.

Word	Noun	Adjective	Verb	Adverb
leftism	Yes	No	No	No
political theory	Yes	No	No	No

As nouns, political theory is a hypernym of leftism; that is, political theory is a word with a broader meaning than leftism:

leftism: the ideology of the political left; belief in or support of the tenets of the political left
political theory: an orientation that characterizes the thinking of a group or nation

Other hypernyms of leftism include ideology, political orientation.

leftism (noun)	political theory (noun)
the ideology of the political left; belief in or support of the tenets of the political left	an orientation that characterizes the thinking of a group or nation