Why is it necessary to dig so far to understand the decay of American democracy? Today's problems are impossible without simple gerrymandering and the idiosyncrasies of the electoral college. It's not a deep problem.
They are subject to repair.
Our nation's brightest political theorists such as Lawrence Lessig have put forth simple solutions to their credit. Theres the majority vote interstate compact which has been ratified by many states already. Simple vornoi redistricting would solve the gerrymandering problem.
Ideologies and philosophies don't build civilizations. They distract otherwise capable people. Practical circumstances shape civilizations. That's really the major lesson of the classics if you read them.