You say that a huge Biden victory allows establishment Democrats to pull the 2020 card whenever progressives act up. I believe there could be some element of that, but I think there will also be pressure on his administration (and possibly a Dem Congress) to perform like nothing before.
Bernie Sanders, AOC, Ilhan Omar, etc were not well known a decade ago. I believe there will be more fellow Democrats holding the Biden admin's feet to the fire than before.
To apply pressure on somebody, you need one of two conditions:
1. What you want to get him/her to do is something (s)he actually already would do but just needs to be reminded of. This can take multiple different forms, such as having been scared to do it and just needing to muster the courage, or having slipped on his/her own standards and needing to get back to listening to his/her conscience again. But one way or another, it needs to be something (s)he already has some motivation toward.
But that condition does not apply to Biden and progressive politics. The only times he ever mentions anything progressive are to badmouth it. He answers questions with built-in right-wing framing with full acceptance of that framing and gives Republican-sounding answers (at least pre-2016 Republican). This is the behavior of somebody who sees the left as more of an enemy than he sees the right.
So, what about the other condition...
2. It's something (s)he doesn't want but can be threatened into if some other thing (s)he does care about it is at stake.
But what's at stake for Biden to be threatened over? Re-election? He already doesn't sound like he cares much about that. Return to the Senate? He already left several years ago, which is not much of a sign that he wants to go back. His legacy? What he values most for a legacy is his how much he can be remembered as the great cooperator with the other party, not for defeating them at something, so if that puts anybody in a position to be able to put pressure on him, it's them. "Do this to be remembered as bipartisan" is a motivator for him; "Do this to be remembered as progressive and helping the people" is not.
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I have to wonder what exactly he thinks they're supposed to do there, and what anybody who plans on hanging around at a polling place all day thinks they're supposed to do there. Anything somebody did that could skew the results wouldn't be visible to someone who's just hanging around anyway.
Trump Tweets
PEACE THROUGH STRENGTH (BRING OUR SOLDIERS HOME). VOTE!
SAVE OUR SECOND AMENDMENT. VOTE!
FIGHT THE CORRUPT FAKE NEWS MEDIA. VOTE!
PROTECT PREEXISTING CONDITIONS. VOTE!
BETTER & CHEAPER HEALTHCARE. VOTE!
PRO LIFE! VOTE!
MASSIVE REGULATION CUTS. VOTE!
SPACE FORCE. VOTE!
BEST V.A. EVER. 91% APPROVAL RATING. VOTE!
401(K). VOTE!
BIGGEST TAX CUT EVER, AND ANOTHER ONE COMING. VOTE!
It's weird how many of these are things he already did or could have done but didn't. It's like he thinks the current President is somebody else and he's running against that guy. People said the same thing about his ads with videos of protests happening under his own watch but messaging saying that's what we'd get if Biden were elected, but at least in that case, if could be passed off with "well, they're on Biden's side, though, so with him we'd be getting even more of that". But these are not reactions by the populace; they're direct Presidential actions. "Bring our soldiers home"? Yes, why haven't you? "Better & cheaper health care"? Yes, why do you not only never offer a better system but even keep trying to kick people out of health care completely and favoring the system that gave us the runaway pricing?
Looks like someone finally got their phone back.
It's not like him to post such short bursts of... whatever that is, though. He's obviously not well.
Maybe he's dictating while gasping & wheezing.
Seriously, though, I doubt it's him. There's a consistency of theme and structure running through all ten lines. That would call for more of an attention span than he's demonstrated in the last 15 years.