henchman vs running dog

henchman

noun
  • A person who supports a political figure chiefly out of selfish interests. 

  • A loyal and trusted follower or subordinate. 

  • An assistant member of a criminal gang. 

running dog

noun
  • A lackey; a lapdog; an unprincipled person who helps or flatters other, more powerful and often evil people. 

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