The reason working-class struggles are central to Left politics is that they are the enabling condition for everything else. They create the power and the political leverage that enables us to act on our morals and ideological beliefs — whereas the morals and values without the leverage remain little more than pipedreams. In this third pamphlet, we develop the classic rationale for a class-based political strategy. We examine how it works and also why, even though it deserves to be at the heart of progressive politics, it is so hard to organize and sustain.