The only way the US ever regresses from its current position is through internal disarray. They cannot be challenged by external forces, not in the foreseeable future anyway. Unfortunately, internal disarray of the magnitude required to effect the changes espoused herein are basically impossible without full scale civil war erupting. And that would be bad or worse. When the medicine is worse than the disease, you accept the disease.
This probably isn’t the progressive answer you’d expect, but perhaps under a centuries old definition of progressive: weighted technocracy. People vote only in the field of their own expertise, and leave all other issues to those who have expertise. It is a sort of direct democracy with votes weighted by credentials.
Unfortunately you need an insane amount of checks and balances to make it work without power becoming overly concentrated in a Soviet style steering committee.
Cyteen, by CJ Cherryh, explores this well in a fictional context.