POTUS: Biden, Warren, Sanders, Harris, Buttigieg
VPOTUS: Warren, Harris, Buttigieg, O'Rourke (TX), Booker, Klobuchar (MN), Castro, Ryan (OH)
Biden/Warren or Biden/Harris
Sanders/Harris or Sanders/Klobuchar
Warren/Castro or Warren/Booker
Harris/O'Rourke or Harris/Buttigieg
We see here why, whatever their polling, Buttigieg, O'Rourke, Booker, Castro and Klobuchar remain very relevant.
Warren/Booker --> Warren/Harris
Harris/Buttigieg --> Harris/Brown (Sherrod Brown)
But it underscores that the number of folks very much "in" the conversation at this moment is only eight or so.