Catholic ping!
Two points.
One, the founding father’s limited who had the vote. For the most part it was those that were productive (landowners). As the producers of wealth lost political power at the ballot box, they found other ways to influence politicians.
Two, the change where states no longer appointed Senators but instead allowed voters to decide. The Senators were suppose to look out for the states, while the house looked after the citizens.
These two things took us from a republic to a democracy (that is as the old joke goes, two wolfs and a sheep voting on what is for dinner).