I definitely think that we are constitutional republic nation. I belive that for many reasons. First of all our constitution is designed that keep it that way. When our founding fathers formed the government and society they worked very hard to keep it that way. And its the way it should be. Our constituation is designed to be fair with everyone.
The United States of America is both a constitutional and a representational republic. Our consitution spells out how we elect representatives to serve our needs in House of Representatives, the Senate, and the White House. This is not an either or question that can be answered one way or another. It is easily "both."