I'm not quite sold on it having been a plan to protect Harris and give her the spot without a primary. That strategy would take a ton of coordinstion, but more importantly it throws a ridiculous amount of uncertainty intoix that I think any political party would be too afraid of.

The more simple explanation, in my opinion, is that Biden is exactly what some had thought for over a year now - a person getting older and starting to run into cognitive and physical decline. I've watched multiple family members go through this, and the picture of a person in the middle of decline lying to themselves about their new reality and stubbornly refusing to accept it fits perfectly well.