Sanders has to find constituencies wherever they exist now.

I'm guessing any that would be:

Anti war
universal healthcare
Labor
Anti wallstreet/media/establishment
Legalize weed
Teachers
nurses
Blue Collar
Progressives
Latinos
Muslim
Immigrants
Sex workers

Bidens may be:

Wall street/ the owners
military complex
upper middle class whites
Conservatives
Liberals
Never Trumpers
Blue no matter who
Corporate Media
White collar workers
Pimps
Democratic party

Don't know how accurate that will be. Just a guess.