China has a problem: rising inequality. The gap between profits and wages is soaring. Although elements of the government have sought to boost workers’ incomes, they have been thwarted by major companies and banks “that don’t want to give more profit to the country and let the government distribute it,” Qi Jingmei, a research fellow for a government think tank, told the Wall Street Journal.

Of course, if China permitted the establishment of unions, wages would rise. But for fundamentally political reasons — independent unions would undermine the Communist Party’s authority — unions are out of the question.

Meanwhile, the United States also has a problem of a rising gap between profits and wages. The stagnation of wages has become an accepted fact across the political spectrum; conservative columnists such as Michael Gerson and David Brooks have acknowledged that workers’ incomes seem to be stuck.

What conservatives haven’t acknowledged, and what even most liberal commentators fail to appreciate, is how central the collapse of collective bargaining is to American workers’ inability to win themselves a raise. Yes, globalizing and mechanizing jobs has cut into the livelihoods of millions of U.S. workers, but that is far from the whole story. Roughly 100 million of the nation’s 143 million employed workers have jobs that can’t be shipped abroad, that aren’t in competition with steel workers in Sao Paulo or iPod assemblers in Shenzhen. Sales clerks, waiters, librarians and carpenters all utilize technology in their jobs, but not to the point that they’ve become dispensable.

Yet while they can’t be dispensed with, neither can they bargain for a raise. Today fewer than 7 percent of private-sector workers are union members. That figure may shrink a little more with new “right to work” laws in Michigan — the propagandistic term for statutes that allow workers to benefit from union contracts without having to pay union dues.

Defenders of right-to-work laws argue that they improve a state’s economy by creating more jobs. But an exhaustive study by economist Lonnie K. Stevans of Hofstra University found that states that have enacted such laws reported no increase in business start-ups or rates of employment. Wages and personal income are lower in those states than in those without such laws, Stevans concluded, though proprietors’ incomes are higher. In short, right-to-work laws simply redistribute income from workers to owners.

Why, then, are such laws being enacted? The gap between U.S. capital income and labor income hasn’t been this great since before the New Deal; why widen it still more? The answer, in Lansing no less than in Beijing, is political. The Republicans who took control of the Michigan statehouse in 2010 understand that Democrats’ foot soldiers come disproportionately from labor. GOP efforts to reduce labor’s clout help Republicans politically far more than they help any Michigan-based businesses or local governments. (The legislation, which Gov. Rick Snyder (R) signed into law Tuesday evening, establishes right-to-work requirements for the public sector, too.)

Those who doubt that the intent of Michigan’s laws is more political than economic should consider the two kinds of unions exempted from its reach: police and firefighter unions. Their contracts are among the costliest that local governments confront: Police and firefighters generally (and rightly) retire earlier than do other public employees, with relatively generous pension benefits. But in Michigan, police and firefighter unions often endorse Republicans. Shrinking their treasuries and political power by subjecting them to right-to-work strictures would only damage Republicans’ electoral prospects (and may well play poorly to voters).

With Snyder’s signature, Michigan becomes the second state in the once-heavily unionized, industrial Midwest to adopt such a statute; hitherto, such laws had largely been confined to states in the South, the Plains and the Mountain West. The United Auto Workers (UAW) was once the colossus of Michigan politics, but the union’s membership has shrunk to 381,000 — roughly one-quarter of its size 35 years ago — a casualty of globalization and the legal and cultural obstacles the UAW has encountered to organizing new members.

Michigan Republicans have seen a chance to weaken the UAW and labor’s power at election time. Doing so further diminishes the number of workers who can bargain for a raise. It’s nice that conservatives are finally acknowledging that workers’ incomes are stagnating. But workers don’t get raises if they can’t bargain collectively, and all the hand-wringing about our rising rates of inequality will be so much empty rhetoric unless we insist — in Lansing and Beijing — on workers’ right to form powerful unions.