My own view is that the best way for unions to grow is to combine the strengths of these different strata of the working class. SEIU has tried this, in a way. From its base of hospital workers and janitors (middle-stratum jobs), the union has made incursions up and down, attempting to organize adjunct professors and fast-food workers. The challenge of these campaigns is that the workers are spread across an entire metropolitan labor market. These groups don’t necessarily feature in one another’s lives in any way other than as consumers; they are unlikely to live next to one another, or play sports together, or get drunk together, or share spaces of worship. Their kids aren’t friends or even classmates. The union’s ability to throw its existing weight into new workplaces is thus limited by the social distance separating the organization’s existing base from its areas of expansion.

Our registered nurse, custodian, and fast-food worker, in other words, aren’t necessarily going to take risks on one another’s behalf. The union wants them to understand their fates as intertwined, but given hierarchies of race, economic position, and social status, that understanding is not going to come easily. Such an approach might work incrementally, as SEIU has found with its success in adjunct organizing campaigns — funded by janitors, organized by professionals. But to produce significant results, the labor movement needs to focus on where it can maximize whatever strategic resources it still has.

The members themselves are the most underused resource. America once had factories where thousands toiled together. Though divided by race, ethnicity, and skill, the great plants and mills were hothouses of proletarian consciousness. While such work sites are now extremely rare, their lesson should be remembered. The most promising targets for campaigns are employers large and multifarious enough to implicate workers of many different kinds, as well as the broader community. Hospitals, school systems, and universities leap out as potential targets. These are the institutions where the RN, the custodian, and the fast-food worker are under the same roof. They might actually know one another. The meaning of their alliance might cut across lines of race, gender, and status.