Much of the blame for middle-class dominance in political talk “comes from the cold war attack on the left and labor movement,” Zweig says. “Talk about the working class is symbolic of militant, anti-capitalist rhetoric. There was a stigma attached to it.”

The working class holds a privileged place on the left traditionally, both in theory and practice. Socialists and other leftists saw workers as most directly exploited by and in confrontation with capitalists, most likely as a result of their collective work to develop a class solidarity, and thus the indispensable challenger to capitalist control and natural vehicle for a social control of productive assets. In practice, working-class political and union movements were some of the major creators of progressive change, democracy, equality and social solidarity.

In the United States, the opinion-making elite celebrated the middle class as the force for stability and democracy as well as the standard of aspiration for the rest of society (even though that same middle class often was the base for reactionary politics). The working class, if not tamed by the middle class, could be a threat to the social order.

But in recent decades, especially among intellectuals, the working class lost its theoretical primacy as a potential radical force for change to blacks, women, gays, marginalized people, a global “multitude” and other groups. “Working class” was often implicitly reduced to “white blue collar men,” even though most of the groups identified in the new identity politics were also working class, albeit with distinct experiences, even if the movement leaders often were not (and “middle class” individuals also led many unions or other working class organizations). Also, in practice, unions were collapsing, and the Democratic Party turned more towards its middle class and professional base.

When asked, few Americans will volunteer that they are in the working class, but many accept it once they are presented with the term. The 2012 General Social Survey asked a national sample of adults whether they would say they belong in “the lower class, the working class, the middle class, or the upper class.” Forty-four percent chose working class and 44 percent chose middle class.

To be sure, the working-class label has long been mildly pejorative. In television series of earlier decades, such as “The Honeymooners” and “All in the Family,” the working-class man was sometimes depicted as a buffoon or bigot. Today, as the college-educated middle class has expanded and factory work has declined, the working class has come to be seen as encompassing those who haven’t made it economically. And if you are not upwardly mobile in America, many people think it’s your own fault. In a 2012 Pew Research Center national survey, 38 percent thought that poverty was caused by a lack of individual effort, 46 percent said it was due to circumstances beyond a person’s control, and 11 percent thought both factors were involved. Politicians may prefer to call working-class families by the class position they aspire to rather than the one they hold.