The disparity of wealth in this country is reaching an extreme that threatens to eclipse America’s middle class – the anchor of this country’s political stability, social fabric and economic growth since World War II.

This obvious fact remains hidden in plain sight, obscuring the real issues which should be the focus of our current political debate about how to improve the plight of those sliding down the economic ladder.

A PBS NewsHour program, “Land of the Free, Home of the Poor,” recently explored the issue by highlighting a dramatic set of statistics: The most affluent 20 percent of Americans own 84 percent of the nation’s personal wealth, while the poorest 40 percent own just .003 percent (or essentially none) of it.

More surprising than the statistics were the impromptu public reactions elicited in interviews, conducted by a PBS reporter who displayed various wealth-distribution pie charts to tourists standing on line for “David Letterman Show” tickets in Times Square and asked them which best represented the U.S.

Most of those interviewed — presumably self-identified members of the middle class — opted for pie charts showing relatively equal distributions of wealth. The chart which reflected the actual, and most skewed, distribution of wealth they identified as typical of a Third World country, like India, rather than the U.S.

The interviews didn’t touch upon an even more shocking statistic – that those at the pinnacle, the top 1 percent, owned over 34 percent of the country’s personal wealth and earned 23.5 percent of its personal income as of 2007 (before the current recession made things worse for those down the food chain by eliminating jobs, homes and hopes for millions). Statistics also suggest that the income-wealth chasm has been steadily widening since the 1980s.

It appears, then, that the average Dick and Jane don’t realize they’re an endangered species.

Perhaps this explains the widespread public illusion that middle class can quickly rebound if only political leaders will embrace a magic formula for restoring prosperity — a simple cure-all, like, say, getting government “off the backs” of business and working families.

Contrary to right-wing dogma, the increasing impoverishment of the middle class is due less to government distorting the free market by over-regulating, over-taxing and over-spending than to the mechanics of the market itself.

Disparities of wealth are an inevitable consequence of a free-market system, and, though they can provide a beneficial incentive for hard work and ingenuity, they can also become destructive if carried to an extreme.

The fact is it takes money (“capital”) to make money. Those who already have plenty of it usually prosper more in boom periods and fare better in downturns. The effect is cumulative over time. And their children start life with a considerable leg up, thanks to safer neighborhoods, better schools, more nutritious food, higher quality health care and the right connections to find good jobs.

Only government can level the playing field a bit – at least enough to prevent terrible economic suffering and social and political turmoil. I’m not talking about hijacking the economic ship, as in Socialism or Communism, just making a course correction similar to the way anti-trust laws intervene to prevent concentrated business power from leading to monopoly.

What can government do? In large part, the same as it has done in the past, but with greater focus upon efficient operations, effective programs and fraud prevention. It can impose a more progressive tax rate on incomes to increase revenues, and then use a chunk of the additional revenues to fund benefits that increase opportunities for those attempting to climb the economic ladder. At the top of that list should be loans, grants and subsidies for education and job retraining. In the jargon of economists, this is an exercise, albeit a limited one, in “wealth transfer.”

It’s not necessary or wise to go back to top tax marginal rates of between 70 percent and 92 percent, which were in force between 1945 and 1980. Such steeply banked rates would serve to either kill incentives or encourage tax evasion. The Clinton-era structure, with a top rate of about 44 percent, will suffice.

Progressive taxation isn’t “punishing success,” as the wealthy argue. If they didn’t live in a privileged bubble, isolated from the day-to-day reality of the struggle for survival, they might realize it was in their self-interest to give up a small slice of their bigger piece of pie.

. For one thing, about 70 percent of national economy activity comes from consumer spending. The unemployed, underemployed and working poor can’t spend what they don’t have, particularly with credit scarce. The result is recession or worse. Many economists believe that income inequalities helped trigger the Great Depression of the 1930s, because demand began to lag behind the economy’s growing capacity to mass produce automobiles and other consumer goods.

For another, poverty and unemployment stresses families and especially children, leading to a host of other social ills that ultimately impact everyone — crime, substance abuse, poor school performance and disease. A recent study found that some 31 million children currently live in poverty, a nearly 20 percent increase from 2000, and that kids who slip even temporarily into poverty are less likely to be successful in school or graduate and more likely to have longterm health problems.

Finally, blatant extremes of wealth and poverty are bound, sooner or later, to ignite smoldering resentments that can flame up into civil unrest or even revolution which overturns the established structure of society. Violence against the “system” is the last resort of desperate people.

Billionaire investor Warren Buffett has nicely summed up the reason for the affluent to share more of the pie, “there’s a lot of serendipity. We — everybody in this country — owes their good fortune in some way to the rest of the country.” In other words, we are all interdependent for our success.