I don't think Harris is a foregone conclusion. Let us not forget that Biden's undoing was not his dementia, but his poll numbers. If they can't get Kamala within striking distance before the convention, the poll numbers will be her undoing as well. I expect to see quite a push here in the next week and a half, and if Harris is still not within the margin of error in the swings states after that, there will be an open convention.
Biden's undoing has been Biden.
Americans may not seem, on average, the brightest stars in the sky (if you believe the mass media's sanctimonious garbage), but it doesn't take much to figure out his aggressive policies toward traditional energy forms have cost Americans at every turn, from the gas pump to the dinner table to the thermostat on the wall and every light in the house.
None of this makes any sense.
Add to that the Government sponsored invasion by over 11 million people, unvetted, often criminal, set up with housing and cash and transportation, and paid for by our hard-earned dollars or by cutting benefits to veterans and even welfare recipients, and people are getting fed up.
Then he frequently goes on angry diatribes against the very people who are footing the bill.
I'd say there are a lot of people out there who are simply p.o.ed at the whole setup. Add in the rabid 'get Trump' attitude, the actions taken toward J6-ers, the propaganda, the lies, the tacit treatment of the electorate as if they are stupid, the riots in the streets which get no pushback, while peaceful elderly men are dragged from their beds at 4 AM by tactical teams (if not shot) in grandstanding operations with the media all gathered to 'witness' the 'takedown', and the bullshit gets too damned deep to remain civil.
Either you support that crap or you oppose it, but I really don't think there are that many on the fence, and support is dwindling as people look past the lies on TV and see with their own eyes.
By their fruits ye shall know them, and the whole shipment is rotten to the core.
