The other day I found myself reading a leftist rag that made outrageous claims about America. It said that we are becoming a society in which the poor tend to stay poor, no matter how hard they work; in which sons are much more likely to inherit the socioeconomic status of their father than they were a generation ago.

The name of the leftist rag? Business Week, which published an article titled "Waking Up From the American Dream." The article summarizes recent research showing that social mobility in the United States (which was never as high as legend had it) has declined considerably over the past few decades. If you put that research together with other research that shows a drastic increase in income and wealth inequality, you reach an uncomfortable conclusion: America looks more and more like a class-ridden society.

And guess what? Our political leaders are doing everything they can to fortify class inequality, while denouncing anyone who complains - or even points out what is happening - as a practitioner of "class warfare."

According to estimates by the economists Thomas Piketty and Emmanuel Saez - confirmed by data from the Congressional Budget Office - between 1973 and 2000 the average real income of the bottom 90 percent of American taxpayers actually fell by 7 percent. Meanwhile, the income of the top 1 percent rose by 148 percent, the income of the top 0.1 percent rose by 343 percent and the income of the top 0.01 percent rose 599 percent. (Those numbers exclude capital gains, so they're not an artifact of the stock-market bubble.)

As a general rule, once they've reached their 30s, people don't move up and down the income ladder very much. Conservatives often cite studies like a 1992 report by Glenn Hubbard, a Treasury official under the elder Bush who later became chief economic adviser to the younger Bush, that purport to show large numbers of Americans moving from low-wage to high-wage jobs during their working lives. But what these studies measure, as the economist Kevin Murphy put it, is mainly "the guy who works in the college bookstore and has a real job by his early 30s." Serious studies that exclude this sort of pseudo-mobility show that inequality in average incomes over long periods isn't much smaller than inequality in annual incomes.

Business Week attributes this to the "Wal-Martization" of the economy, the proliferation of dead-end, low-wage jobs and the disappearance of jobs that provide entry to the middle class. That's surely part of the explanation. But public policy plays a role - and will, if present trends continue, play an even bigger role in the future.

Put it this way: Suppose that you actually liked a caste society, and you were seeking ways to use your control of the government to further entrench the advantages of the haves against the have-nots. What would you do?

One thing you would definitely do is get rid of the estate tax, so that large fortunes can be passed on to the next generation. More broadly, you would seek to reduce tax rates both on corporate profits and on unearned income such as dividends and capital gains, so that those with large accumulated or inherited wealth could more easily accumulate even more. You'd also try to create tax shelters mainly useful for the rich. And more broadly still, you'd try to reduce tax rates on people with high incomes, shifting the burden to the payroll tax and other revenue sources that bear most heavily on people with lower incomes.

Meanwhile, on the spending side, you'd cut back on healthcare for the poor, on the quality of public education and on state aid for higher education. This would make it more difficult for people with low incomes to climb out of their difficulties and acquire the education essential to upward mobility in the modern economy.

And just to close off as many routes to upward mobility as possible, you'd do everything possible to break the power of unions, and you'd privatize government functions so that well-paid civil servants could be replaced with poorly paid private employees.

It all sounds sort of familiar, doesn't it?