2015 article by John Bachtell, Chairman of the National Committee of the Communist Party USA on need to work through the Democrat Party to achieve his Party's goals (which are quite similar, if not identical, to Progressive's goals). As an aside, he considers a lot of things to be extremist that Spence does. Maybe Spence considers CPUSA to be "centrist" or "moderate"?:
https://www.peoplesworld.org/article...party-i-agree/