Imagine America without unions. This shouldn’t be hard. In much of America unions have already disappeared. In the rest of America they’re battling for their lives.

Unions have been declining for decades. In the early 1950s, one out of three American workers belonged to them, four out of ten in the private sector. Today, only 11.8 percent of American workers are union members; in the private sector, just 6.9 percent. The vanishing act varies by region—in the South, it’s almost total—but proceeds relentlessly everywhere. Since 1983, the number of states in which at least 10 percent of private-sector workers have union contracts has shrunk from 42 to 8.

Following the 2010 elections, a number of newly elected Republican governors and legislatures in the industrial Midwest, long a union stronghold, moved to reduce labor’s numbers to the trace-element levels that exist in the South. A cold political logic spurred their attacks: Labor was the chief source of funding and volunteers for their Democratic opponents, and working-class whites, who still constitute a sizable share of the electorate in their states, were far more likely to vote Democratic if they belonged to a union. The fiscal crisis of the states provided the pretext for Republicans to try to take out their foremost adversaries, public-employee unions.

Put aside for a moment the particulars of the Chicago teachers’ strike and look at the broader picture. Rahm Emanuel is only one of a number of Democratic mayors and governors who are going after public-employee unions. In Los Angeles, Mayor Antonio Villaraigosa is also at loggerheads with the city’s teacher union. In San Jose, a Democratic mayor and city council scaled back the city employees’ pensions (and so did city voters when they were asked to ratify that decision). In New York, Governor Andrew Cuomo has tangled with a number of public-sector unions. The battle between management and labor seems to have spread to the very center of the Democratic Party.