The demise of the U.S. political system (often called Democracy, a misnomer for sure) has two systemic (structural) components:

1) An economic system which promotes inequality (e.g. concentration of wealth) and as a result extends to the social realm, creating a permanent underclass that has been deprived of education and the possibility of attaining the basic necessities of life. This is agnostic to the political party in power as they both advocate the same economic/social framework.

2) Systemic racism and the continuation of a caste system (based on economic, social and racial divides, vide the religious right) that has never been attacked head on since the inception of the republic. Yes, there have been improvements (hard fought) but, given item (1) these advances have been clawed back. We find ourselves in the position of fighting for the same things (under a different name) that we fought for decades, nay, centuries ago.

Voting is the opiate of the masses. Every 4 years someone comes along and pays lip service to issues and causes that are in vogue. But little is done to address the systemic (structural) failures of the system, because the elected are being guided by the same forces in (1) - no matter what party they belong to.

"The liberals can understand everything but people who don't understand them."
Lenny Bruce

"The cleverest of all, in my opinion, is the man who calls himself a fool at least once a month."
Dostoevsky