How do six principles of the constitution make the U.S. different than other countries?
Here are the six principles.
Popular Sovereignty,
Limited Government,
Separation of Powers,
Checks and Balances,
Judicial Review,
Federalism
Many democratic countries have the first two principles. Most do not have the last four.
Check this site for more information.
http://www.virtualclassroom.net/tvc/gov/constitution/