The socialists’ theory of the past decade of national politics is that conventional, corporate Democrats lost the working class to President Donald Trump.

Graham Platner, a Democratic Senate nominee, faced a campaign collapse. A sexual assault allegation surfaced, leading to widespread criticism and withdrawal of support. Platner…

Democrats eager to win back working-class voters have been torn between a more populist, left-leaning message or a more centrist, moderate approach. They went with the populist…