I think the 2020 elections have potential to change politics as we currently know them forevermore. It's the perfect opportunity for the Democratic Party to either assert it's middle-of-the-road dominance over the Socialist wing, or not, as well as allow the Republican Party to either reclaim it's Grand Old Party roots, or not.
Ideally, after the primaries we'll enter the General Election with 4 candidates, a mainstream Democrat, a Socialist, an Independent who can reclaim the Republican brand, and the incumbent. That would eventually show us the real mood of the country.