Actually, the U.S. never was.  We have never been a Democracy.  A democracy can be thought of as 4 wolves and a sheep voting on what to have for dinner.  The U.S.A. is a democratic Republic.  The ‘democratic’ part means that we elect our leaders in a majority vote.  The republic part means we are under the rule of law and our elected representatives are accountable to us.

Here is a video that explains the different forms of government.  It does a pretty good job of explaining the difference between a democracy and a republic.

I just wish that this video were played in every Social Studies class in the country at least once a year.