What would America be like without a constitution?

Either England, or Nazi Germany. Our Bill of Rights is a copy of the English Bill of Rights, but it requires a 2/3 majority of both houses and the states to be changed. That is why our right to bear arms is active, and they have ignored theirs since the turn of the 19th century. On the other hand, our system was modeled on Frederick the Great's. Multi-party democracies are not encouraged since the elections are winner-take-all and minor parties cannot form coalition governments. So any of our Presidents could have become a dictator quite easily if there was no mechanism to stop him.