A separate Pew poll found 56 percent of Americans saying their incomes are "falling behind" the cost of living. But at higher income levels, a majority said their incomes are either staying even or going up faster than living costs.

Income inequality in the U.S. dropped sharply in World War II and remained fairly steady until the 1970s. Unlike the gap in many developed nations in Europe and other regions where living standards have improved without exacerbating inequality, the American gap has steadily grown. From 1975 to 2002, the percentage of U.S. income earned by the richest 10 percent (now about 30 million people) of the population increased from 33 percent to 45 percent. The portion held by the richest 3 million people doubled, from 8 percent to 16 percent. And the share held by the richest 300,000 people tripled, from 2.25 percent to 6.73 percent.

. Conservatives argue that inequality is the inevitable and even desirable consequence of a free-market system that rewards work and talent, and that it gives Americans a greater incentive for success than people have in, say, Sweden. Liberals say that growing inequality is a failure of capitalism and of democratic government. Can the gap between rich and poor continue to widen without causing a political backlash?

57 percent of the income goes unreported. That's $68 billion in unpaid taxes right there.

the study found a tax gap -- the difference between taxes owed and taxes actually paid -- of $345 billion, or nearly one-fifth of all taxes collected by the I.R.S. This sum happens to be just a few billion dollars less than the projected federal budget deficit for 2007; it also amounts to more than $1,000 worth of cheating by every man, woman and child in the U.S.

most Americans say they are proud to pay their taxes. In an independent poll conducted last year for the I.R.S. Oversight Board, 96 percent of the respondents agreed with the statement ''It is every American's civic duty to pay their fair share of taxes,'' while 93 percent agreed that everyone ''who cheats on their taxes should be held accountable.'' On the other hand, when asked what influences their decision to report and pay taxes honestly, 62 percent answered ''fear of an audit,'' while 68 percent said it was the fact that their income was already being reported to the I.R.S. by third parties. For all the civic duty floating around, it would seem that most compliance is determined by good old-fashioned incentives.

Politicians have intentionally set tax rates on wages much higher than those on long-term investment returns. The U.S. has a progressive tax system in the sense that well-paid workers sacrifice much more than poor workers on their “ordinary income.” But Americans with so-called unearned income—qualified dividends and long-term capital gains—get a break. A billionaire investor can pay about the same marginal rate as a $40,000-a-year worker, a fact Warren Buffett has famously lamented.

Washington state had the most regressive state tax system, taxing the poorest residents at 16.8 percent while taxing the top 1 percent at only 2.4 percent, the study said. Florida ranked number two, with the poor paying 12.9 percent of their income to taxes, while the top 1 percent pay 1.9 percent. Texas ranked third, with the bottom playing 12.5 percent and the top 1 percent paying 2.9 percent.

, the poorest 20 percent of Americans paid an average of 10.9 percent of their income in state and local taxes and the middle 20 percent of Americans paid 9.4 percent. The top 1 percent, meanwhile, pay only 5.4 percent of their income to state and local taxes.

It’s time for the wealthiest Americans and big corporations to pay their fair share of taxes. When they take unfair advantage of the many loopholes in the tax code the rest of us pick up the tab.