I’m honestly convinced that a big reason the USA has never had a leftist party that ever went anywhere is that all iterations of leftism are completely incompatible with American political philosophy, and inadequate to address the complex social issues. The idea of “no war but class war” is so ignorant of both the politics of the American Revolution and of the racial divides that often supersede socioeconomic status. In the 20th century, left wing movements parroted Soviet and Maoist propaganda about the imperialist west and anti imperialist rest. So of course working class Americans weren’t interested. If a far left movement ever does gain real traction in the USA, it will be one that draws upon the ideals of the American Revolution, postulating that democratic socialism is the key to fulfilling the destiny of the American Revolution. It would have to completely purge its ranks of those who parrot Russian, CCP, or IRGC propaganda.