Sleeping Giant Meaning

(idiomatic) Someone or something with great, latent strength.

Example: 1926, "The Educational screen: Volume 5", quoting CE Mahaffey, President, Department of Visual Education, Northwestern Ohio Teachers,
  "There is a sleeping giant in education that is just beginning to awaken."
2010 circa April 30, Sophia Tareen for the Associated Press, "Anger over Ariz. immigration law drives US rallies", as reprinted in USA Today [1]:
  Angered by a controversial Arizona immigration law, tens of thousands of protesters […] rallied in cities nationwide […] .
  "I want to thank the governor of Arizona because she's awakened a sleeping giant," said labor organizer John Delgado, who attended a rally in New York where authorities estimated 6,500 gathered.