Barney Frank and Ed Rendell are right. In seeking to recall Wisconsin Governor Scott Walker, the public-sector unions and their allies on the progressive wing of the Democratic Party made a big mistake. “My side picked a fight they shouldn’t have picked,” Frank told The Hill. “People need to be more strategic about the fights they pick.” In other places, such as Ohio, Democrats have successfully campaigned in state legislatures to roll back Republican anti-union initiatives. But rather than following such a strategy in Wisconsin, they tried to drive Walker out of office, alienating independent voters and bringing down upon themselves a deluge of conservative money.

This overreach may well embolden G.O.P. governors in other states to follow the Wisconsin example. But the tactical blundering of the anti-Walker forces shouldn’t be allowed to obscure what is at stake here. Exploiting public concerns about debts and deficits that have resulted from an economic downturn largely brought on by Wall Street malfeasance, Republican politicians, backed by wealthy individuals and corporations, are looking to cripple the unions and balance local budgets on the backs of low- and middle-income workers.

In short, it’s a class conflict. On one side are right-wing billionaires like the Koch brothers and Sheldon Adelson, who exploit quirks in the campaign-finance laws and anxiety among taxpayers to further their conservative agendas, and shadowy corporate-financed organizations, such as the American Legislative Exchange Council, or ALEC, which helped draft many of the anti-union bills that Republican statehouses have adopted. On the other side are teachers, janitors, municipal administrative workers, cops, and firemen.

Over the years, to be sure, some public-sector unions have adopted restrictive practices and negotiated retirement agreements that can no longer be sustained. (At a time when New York City is laying off teachers, can it justify paying retired policemen and firefighters up to two-thirds of their peak salaries after just twenty years of service? I don’t think so.) But Republicans like Walker aren’t merely looking for concessions from the unions: they are out to destroy them.

Americans are famously reluctant to adopt the language of class warfare, or even to acknowledge its existence. In its place, they have embraced the argot and imagery of individualism: The hardy frontiersman loading his family and his possessions into a single wagon; the industrious immigrant tending his grocery store or gas station sixteen hours a day; the spotty post-adolescent hunched over his laptop trying to create the next Facebook.

And, of course, the Horatio Alger narrative isn’t completely without foundation. Endowed by nature with fertile land, abundant minerals, and a hospitable climate, and endowed by its founders with democratic and pragmatic approach to politics, the United States has for centuries provided a ready platform for creativity, hard work, and material advancement. From the Irish and Italians to the Vietnamese and Koreans, successive waves of immigrants have moved from the city tenement to the suburban subdivision. Even today, many working-class Mexicans, Haitians, and people of other nationalities are risking their lives to get here.

But individualism is only part of America’s story: class conflict has always played a big role, too. The antebellum plantation economy was based on slavery, a legally sanctioned form of class warfare in which the workers had no rights. In the late nineteenth century, the rise of U.S. industrial might was marked by bitter, violent labor disputes, such as the great railway strike of 1877 and the deadly Homestead Strike of 1892. During the first three-quarters of the twentieth century, organized labor made great advances, many of which it has lost during the past thirty years.

Even when the economy is growing, there are constant conflicts about who gets what. The argument of free-market economists that productivity determines wages and profits is mistaken. Productivity determines the over-all size of the pie. How it is distributed depends on a variety of factors, including relative bargaining strength, international competition, labor laws, and the results of elections. Economics and politics aren’t separate spheres. They are two sides of the same coin, something that is particularly evident in the treatment of public-sector workers. With taxpayers footing the bill, every labor contract has political connotations.

When the economy stops growing, the distributional conflict intensifies, and the outcome can go either way. In the Great Depression, F.D.R. pushed through the Wagner Act, which gave workers the legal right to found unions and bargain collectively. During the postwar decades, partly thanks to the negotiating clout of the trade unions, many ordinary Americans with no great education did so well that they stopped thinking of themselves as working class; with their houses in the suburbs and their cars, they believed they had joined the prosperous “middle class.” Class conflict was a thing of the past.

That didn’t last very long. In the early nineteen-eighties, during another economic slump, Ronald Reagan fired the striking air-traffic controllers, launching what has turned out to be a thirty-year onslaught on trade unions and workers’ prerogatives. Under successive administrations, labor laws were weakened, and those that remained on the books were no longer vigilantly enforced. Union membership fell sharply—from twenty per cent of the labor force, in 1983, to twelve per cent, in 2011. (In the private sector, the decline has been even more precipitous.)

Not entirely coincidentally, inequality rose and wage growth started to lag behind productivity growth. The share of over-all income that goes to wages and other forms of employee compensation began to fall. In 1990, according to calculations by the Bureau of Labor Statistics, about sixty-three per cent of over-all income went to wages and employee benefits. By the middle of last year, the figure had fallen to fifty-eight per cent—the lowest level in many decades.

Commensurate with the decline in labor’s share of income, the share taken by owners of capital has gone up. To be sure, many of these “capitalist” beneficiaries are themselves workers who have invested in stocks through their retirement accounts and personal portfolios. But the richest five per cent of households, who own about seventy per cent of the country’s financial wealth, have reaped most of the gains. And the top one per cent, which owns about forty per cent of over-all financial wealth, has benefitted most of all.

It is in this context that the Koch Brothers, Sheldon Adelson, and their agents in the G.O.P. are engaged in their latest anti-union crusade. The long-term goal is reduce public-sector unions to the same subjugated state as their counterparts in the private sector. On Tuesday, with an assist from their enemies, they won a big battle. But the war goes on.

Photograph by Seth Perlman/AP Photo.