Well, I suppose that’s true. Of course Joe could throw his weight to someone who already ran against Trump, beat Trump in the popular vote, and who he knows well and might have a certain loyalty to. Her name, Hillary, I think.

Who could round up the Dems quicker than anyone? Who could raise money?

I'm not sure Hillary could do either of those things better than Harris. She's basically been retired from politics for nearly eight years. Sure, she has a hand in - but she's been mostly out of the game for a while. The relationships you need in order to "round up" the main elements of the party and to raise money from major Democratic donors are things that have to be maintained and cultivated and fostered. And Clinton not only has huge negatives among the GOP and independents that haven't faded from 2016 (which is why she lost that campaign), but she's probably more intensely disliked by the progressive base than any other alternative. Both for denying them their Sanders dream and for the various things she's done over the last eight years, most recently to scold progressives on Israel/Gaza. Passing up Harris for Clinton would tear the party apart more assuredly than leapfrogging her for Newsome or Whitmer.

Again, idle fancy - I can't imagine Joe looking in the mirror and deciding he can't beat Donald Trump. He's the only one who ever has, after all....