Protest is related to Cause. Cause is a synonym of Get. 
Park is related to Public. Public is similar to National. National is related to Liberty. Liberty is etymologically related to Liberal. 
Protest <--RelatedTo--> Cause <--Synonym--> Get 
Park <--RelatedTo--> Public <--SimilarTo--> National <--RelatedTo--> Liberty --EtymologicallyRelatedTo--> Liberal 