There aren't any independents positioning themselves to run (Howard Schultz rumors to the contrary, and besides, how likely is it that Starbucks is going to mobilize the masses?), so it will be D vs. R in 2020, and the DNC will make sure R will win.  In a sane system, the DNC would be foaming at the mouth over all the disenfranchisement plots, such as the one our glorious SCOTUS just upheld in Ohio, except for one, small thing: Those plots help the DNC.  The folks losing their voting privileges would be voting for progressives, not the neoliberal stooges the DNC keeps foisting on us, so the Rethuglican vote suppressors are actually helping the DNC tools maintain control over the Democratic Party.