Populism is perhaps best understood as a rhetorical style. Even it's "best" left-leaning varieties, it's a framework where society is divided into two contending groups "the people" and "the elite." This implies two things: One, that old class identities, forms of particularism, have to be broken down. There is no room for a working class with interests sometimes counterpoised to middle class or "petit bourgeois" elements—they are all "the people." I'd rather have a labor party with socialist politics...
^^^^ CB: Working class partisans aim to draw the petit bourgeoisie to the side of the working class in the final conflict.