Do high-income persons pay their fair share in taxes?

The notion that they don't has been an American shibboleth for years. Every few months, newspaper are filled with reports showing hundreds of persons making $200,000 and up have escaped payment of taxes entirely.

And a Roper Organization poll published in July found that Americans by and large believe that more than half of all persons with incomes of $500,000 a year and more pay no federal income taxes whatsoever.

At the same time, conservatives complain regularly that high-income persons are being taxed at confiscatory rates, with most of them in the maximum 50 per cent tax bracket. The controversy seems never to end.

Now, the Treasury has come out with a detailed study of actual tax returns filed by high-income Americans that contains some reassuring news - and some worrisome conclusions - about how high-income persons are taxed.

The survey shows first that relatively few high-income persons actually escape payment of taxes entirely, and that their number has decreased dramatically in the past few years.

At the same time, it shows only a small fraction of high-income Americans really is taxed at anything near the maximum 50 per cent rate. And a disturbing number pays so little in taxes it amounts to less than the minimum for wage-earners.

There are these findings:

Despite popular perceptions of widespread tax-avoidance, most high-income taxpayers pay substantial amounts of federal income tax.

In 1976, more than two-thirds of those with incomes of $200,000 or more paid more than 30 per cent, of their total income in federal taxes, while more than 85 per cent paid a 20 per cent rate or higher.

Only 2 to 3 per cent of all high-income taxpayers paid less than 10 per cent of their income in federal taxes.

Over the past few years, the number of persons with incomes of $200,000 or more who escaped payment of taxes entirely has declined dramatically - from 215 in 1975 to 89 in 1976.

The number in the $100,000-and-up category dropped from 901 to 622.

Moreover, many of those who managed to avoid federal taxes did so because the law gives them credit for taxes paid to foreign governments on income earned abroad, or because of deductions for casualty losses - both legitimate.

At the same time, there still are a large number of high-income taxpayers who pay only a token tax or virtually no tax at all, while those with wage-and-salary income are paying rates ranging from 14 to 50 per cent.

The number of these "nearly non-taxables," as the Treasury calls them, in the $200,000-and-up brackets totaled about 500 in 1976 - far higher than most Americans would like to see.

Of those whose total income amounted to $200,000 or more, some 3,400 paid less than 15 per cent of their income in federal income taxes. Among those in the $100,000-and-up bracket, the number was 11,400.

Moreover, although these figures may seem low, experts say they probably understate the problem. The statistics don't include income from tax-exempt state and local bonds, which are a major source of income for some taxpayers.

A relatively small portion of high-income taxpayers actually pays tax rates of 50 percent or more. For the $200,000-and-up group, the number amounts to 8.7 per cent. Among those making $100,000 or more, it's 0.6 percent.

To those who have followed congressional tax changes in recent years, the reduction in the number of high-income persons who escape payment of taxes altogether may not be all that surprising.

The phenomenon stems from two changes Congress made in 1976: First, it cracked down sharply on the use of tax shelters by high-income investors. Second, it stiffened the "minimum tax" enacted to prevent tax-avoidance.

Both Treasury and congressional tax experts agree it's the toughening of the minimum tax that really reduced the bulk of the abuses. It's been the single biggest reason more taxpayers can't dodge taxes altogether.

The difficulty is, Congress now seems bent on undoing at least part of the 1976 crackdown, by reducing the taxes on capital gains and watering down the minimum tax. Capital gains are profits from the sale of stocks or property.

The House already has passed legislation that would lower the maximum tax on capital gains substantially and seriously weaken the 1976 minimum-tax changes - providing $1 billion in new tax breaks, mostly for high-income persons.

And the Senate Finance Committee is considering tripling the net tax break for investors voted by the House, with a quadruple break in capital gains taxes, offset by a slight rejuggling of the minimum tax.

Sen. Russell B. Long (D-La.), sponsor of the proposal, argues it would crack down more harshly on the 2 to 3 per cent who pay less than 10 per cent of their income in taxes, while at the same time providing relief for investors.

Tax experts say there's no doubt Long's plan would reduce the number of "nearly non-taxables" in the Treasury's compendium. But it also could amount to a virtual windfall for some high-income investors.

It's still too early to tell where this year's legislature will end up, and how much fairer - or more unfair - taxation of high-income persons will be when Congress gets through with the present bill.

But the Treasury survey would seem to show that the 1976 changes, while not necessarily ideal ones, did correct a good many abuses that Americans had been worried about - with good reason - in previous years.

The question is, will reversing those now bolster public confidence in the tax system or undermine it? The statistics themselves ought to provide some sort of answer.