Joe's desire to be president AND his willingness to sign off on anything "they" put in front of him is crucial to this venture. They were able to sell Joe as a "moderate". They could not have done the same with Sanders or Warren. Truth is, he is a radical on a very personal level. It shows every single time Joe steps out in front of cameras. Joe has no qualms to personify every inch of this power grab. Heck, he treats US citizens with less respect than he treats the Taliban.