The ONLY state that Dems might turn back blu in the rust belt from 2016 is MI, thats it. No they state here that was red in 16 has any shot at blue in 20.. and honestly if the economy keeps the way its going, even MI will be out of D reach.
Right now, I would say, MI returning blue is about even odds as Mn votes Red in 2020.
The radicalized left has no home in the rust belt outside of IL.
Even MN is going to walk away from what the D party has become, somer or later
The 2020 Election is still nearly 2 years away. Might as well be a lifetime, electorally. Figure, about this time in 2014, we were contemplating the disaster a Hillary vs Jeb Bush 2016 election would entail. End result wound up pretty good.