"Class" is a Marxian concept and for that reason will never make it to a mainstream American party's platform.

The systemic function of the Democratic Party is to keep leftists penned so they don't form their own party with a class message.

The Green Party is not left, it's green, and so it avoids class as an issue as well.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman