Don’t mind me, just taking advantage of a good Marxist meme to plug my Read Theory, Darn it! introductory reading list on Marxism.
As the contradictions within Capitalism sharpen, more and more workers are radicalized and develop Class Consciousness, but without reading theory, this can be taken advantage of by opportunists. The Capitalist machine is very good at this, they redirect problems with the system itself to other areas, like immigrants, queer people, and more. Theory helps cut through that smokescreen and allows us to see how to move beyond Capitalism.
For starters, there are only right and extreme right policies among the Dems and Reps. Secondly, there is a massive pool of disaffected voters that would vote for a lukewarm progressive like Bernie, who was projected to even steal Trump voters, because progressive policy is popular. The Dems ran rightward and lost their voters in general.