The rot set in many years ago -possibly three decades ago. (Read "Democracy in Chains" by Nancy Maclean, please.)
However the first time the rot became obvious was when Obama looked at all the people who had caused and profited from the 2008 financial crash - and gave them jobs in his administration.
Instead of trying them for fraud and putting them in jail, like Iceland did.
There needs to be a special court to try crimes of presidential malfeasance, with the power to send the sucker to jail if found guilty. Instead of a normal jury, which could be pressured, threatened or bought, the jury should be a certain percentage of the whole American people from all ideologies and political parties. Their job is just to find Trump guilty or not guilty of treason, fraud, mass-murder by neglect etc etc.
Until they have come to a verdict, Trump stays under house-arrest in a motel. Not too plush a one, either.
I think he'll confess in a few weeks just to get out of the motel.
If he sticks it out, the sentence should be handed down by the relatives of people who died from covid 19.
You need to keep all politicians just a little afraid of ending up dangling from a lamp post.