short answer:
Ancient Greece
long answer:
Ancient Greece is usually credited with pioneering democracy. All cities of Greece had a set of rules in which they were required to obey. Along with this Greece had a written constitution just like the United States of America, although theirs was called The Constitution of the Athenians. This created a standard in which the people should have behaved and followed. Just like the United States constitution, theirs laid out the governments structure and how the checks and balances of power within it relate to one another.
The united states voting system also has similarities to the Athens, citizens were elected to organize, judge, and make decisions. Every citizen had the ability to speak their mind.
