Looking in on this thread, I think some of you are really asking the wrong questions, practically speaking. You need to understand just how big a role that celebrity and personal charisma play in presidential politics. This next election is all about Trump--either you vote for Trump or against Trump. In our modern society, none of these other 'circus midgets' have any real stature to challenge Trump. If you don't believe it, go look at how Arnold Schwarzenegger became the Governor of Calif.
I think Kamala Harris could win the locked-in blue states like California, Oregon, Washington, New York, Connecticut, Massachusetts, and a few others, but that would be about it. Trump would carry all the big swing states again.
Biden could probably do about as well as Hillary did in the last election, but he's a throwback to the political establishment that got Trump elected in the first place. Few people, including Democrats, have much praise for the Obama administration.
If the dems are going to challenge in this election, they need someone who is fresh, energetic and charismatic -- someone who looks great, speaks eloquently, and "looks the part" of a president.
The dems aren't stupid. They know all this. That's why they're just going to throw as much mud at Trump as they can. That's really their only play right now. Vote democrat because you hate that orange scheister.