TUESDAY'S election results revealed an important fact about this country that ought to be noted before we rush into the Reagan second term and its politics of contentment.

The United States is deeply divided along class lines. According to the ABC News exit poll, Americans earning more than $30,000 a year favored President Reagan over Walter Mondale by more than 2-to-1. But those earning less than $10,000 a year favored Mondale by landslide proportions. The Democrats weren't the only losers on Tuesday; society's losers lost, too.

Who are those people living in families whose total earnings are less than $10,000 a year -- that is, $192 a week, before taxes? That must be a small fraction of the population, isn't it?

No. More than 40 million Americans live in families with incomes of less than $10,000 a year. They are part of an America you didn't see in those feel-good Reagan campaign commercials this fall, an America of poverty and near poverty that is amazingly large, given our image of ourselves as a rich and comfortable nation.

In today's United States, our government tells us, one out of every four children lives in poverty. That is not a typographical error; one in four. Nearly half the working-age adult black men in this country -- 46 percent -- do not have jobs, when the homeless and totally discouraged are added to the conventional "unemployed." The poorest 40 percent of the population (that is, the poorest 100 million Americans) has been earning a steadily declining slice of the national economic pie in recent years, while the wealthy classes have been getting much fatter slices. That bottom 40 percent has actually suffered declining real income over the last five years. The country really has been changing; the poor have been getting poorer, the rich richer.

The fact that things have actually been getting worse so totally contradicts the mood of the country that we tend to shrug it off. The Republicans ignored America's losers this fall; the Democrats, whose past efforts to "solve" the poverty problem came a cropper, made no new proposals. But the situation is getting worse. In 1980 and 1981, 43 percent of black high school graduates in America went on to some kind of college. In 1982, the number fell to 36.4 percent.

In recent years, the number of Americans in serious financial straits has grown appreciably. It even grew in 1983, when the economy began to boom after the recent recession.

This year it will fall slightly as the recovery continues -- but only slightly, despite optimistic predictions to the contrary.

"I am absolutely confident that the poverty rate is going to decline dramatically for 1983," David Stockman told a committee of Congress a year ago. The director of the Office of Management and Budget had to eat those words. When the figures for 1983 came out in August, they showed that 900,000 people had joined the ranks of the officially poor last year, bringing the national total to 35.3 million poor people. The "poverty rate" -- the percentage of Americans below the government's poverty line -- rose two-tenths of a percent to 15.2 percent in 1983. As recently as 1979 the rate was 11.7 percent. Put another way, the number of poor people grew by 8.4 million from '79 to '83, a number equal to the total population of Sweden.

But those officially designated poor are hardly the only Americans who are having a tough time making ends meet. The official standard says that a family of four is poor if its total income was less than $10,178 for the year. But according to another government figure -- one that the Bureau of Labor Statistics stopped publishing in 1981 -- a family of four in an urban area needed $15,323 three years ago to finance a "low" standard of living.

In fact, the "poverty line" was set arbitrarily some 20 years ago at three times the amount a family spends on food -- but not for a normal diet. The government picked an "economy" diet of admittedly inadequate nutritional value as the basis for the standard. A healthy "low- cost" diet would have cost about 20 percent more, and raised the "poverty line" 20 percent higher.

If that higher standard were in effect today -- and many might consider it a more realistic figure -- the number of officially poor people would be about 45 million. Whether officially "poor" or not, this is a fair estimate of the number of strapped Americans right now -- 45 million, twice the population of California, nearly one-fifth of all of us.

Nevertheless, most Americans are concerned not about their countrymen who are having a hard time, but about those who they think are ripping off the system. In another article in today's Outlook, Samuel Popkin reports a revealing recent CBS/New York Times poll finding. When asked who they worry about most, families getting too little welfare or families getting too much welfare, a 2-1 majority said it worries most about those getting "too much." (Among black respondents, revealingly, the numbers are the reverse: by 2-1, blacks worry most about those getting too little help.)

The CBS/New York Times exit poll conducted last Tuesday asked voters if they thought government spending for the poor should be increased, decreased or kept at current levels. Forty percent said the government should spend more, but 39 percent said the current level was enough, and 15 percent said it was too high.

This is an era of declining white guilt. Most Americans believe that they have done their bit for society's losers, who no longer need more help. This is certainly understandable. We made extraordinary efforts to create new opportunities and a new safety net for the poor, and particularly the black poor, during the last generation, but it is difficult to claim that those efforts were successful.

Despite billions spent and sweeping new laws and Supreme Court decisions creating new opportunities for society's losers, the number of losers has declined only about a fourth over the last quarter century, and has actually risen in the last decade. Poverty was nearly halved between 1960 and 1973; it held quite steady until 1979, and has risen sharply since -- whether or not the value of "non-cash benefits" to the poor are considered. We have failed to break the culture of poverty, and for some elements of the population -- notably poor blacks -- conditions have gotten worse despite all our efforts.

This is a shocking record. A decade ago many specialists were convinced that they would see the poverty rate fall to 5 or 6 percent by the mid-'80s; apparently, no one predicted the dramatic movement in the opposite direction. Now we seem to have lost control of the problem, which -- as 1983 demonstrated -- can actually get worse while the national economy is dramatically improving.

Speaking of the 1983 figures in recent congressional testimony, economist Peter Gottschalk of the Brookings Institution observed: "There was a rising tide (the recovery), but it did not lift all boats equally." He attributed this to two factors. First, the poor suffered disproportionately during the 1981-82 recession, and benefited much less than richer Americans from the subsequent recovery. The movements of the national economy do not effect all groups equally or proportionally. Second, demographic changes, particularly the dramatic increase in the number of households headed by women, have increased poverty regardless of the economy's performance. (Nearly half the officially poor Americans live in families headed by women; 35.7 percent of all families headed by women live in poverty.)

Gottschalk, who expressed scepticism at the time Stockman was giving assurances that the poverty rate was about to "decline dramatically," now predicts that the poverty rate will fall by perhaps 1 percent when the 1984 figures are released, and maybe half a percent more if there are two more years of economic growth. In other words, a four-year Reagan boom will only bring the poverty rate back to where it was in 1980.

This suggests an indefinite prolongation of economic hardship for more than 30 million American citizens. The suffering -- dare we call it the exploitation? -- of a substantial minority of Americans remains a permanent, if generally unmentioned, feature of the American dream.

Significantly, some conservatives have acknowledged the need to reach out to the poor and the black to validate the conservative vision of a better America for all its citizens. Rep. Jack Kemp (R-N.Y.) has said often that conservatives won't be able to claim success until their policies benefit the poor as well as the better-off. Adam Meyerson, editor of the Heritage Foundation's Policy Review, wrote recently: "There is a river, a wide Mississippi, that separates the majority of black Americans from the conservative political movement, and until it is crossed conservatives cannot make a full claim to national leadership."

But such voices do not dominate the national conservative movement, or the Reagan administration. Sen. Jesse Helms (R-N.C.) ran successfully for reelection with a blatantly racist appeal to white voters. President Reagan himself took some giant steps backward in race relations during the campaign, denouncing school busing in one community (Charlotte, N.C.) where it has demonstrably worked, to the pride of the local community, and telling an audience in Macon, Ga., that "the South will rise again!," a rallying cry of segregationists in an earlier era.

In the same stump speech, Reagan promoted his line-item veto proposal by asking: "Do you know that that (line- item veto idea) was favored by a leader named Jefferson Davis?" According to The Atlanta Constitution, the crowd -- wildly enthusiastic for most of Reagan's speech -- let that encomium for the president of the Confederate States of America pass in silence.

This has been a bad year for blacks. Their candidates fared poorly, and they saw an alarming revival of race politics in the South. They rallied around Jesse Jackson's candidacy for president, only to be told -- by white politicians and by poll results -- that Jackson gravely hurt the Democratic cause this year. Jackson raised black hopes, and the electorate dashed them.

Of America's 28 million blacks, 35.7 percent live in poverty. Of black families headed by women, 56.1 percent are officially poor. Of the nation's black children, 46.3 percent -- nearly one half -- are in poverty. What are we going to do about this appalling situation?

Encourage more growth, period. That, at least, is the increasingly fashionable answer -- even if growth alone is demonstrably insufficient to solve this problem. Bleeding hearts have gone out of style. Who said life was fair?

America is best understood from its own history. A national preoccupation with money and wealth is as old as the Republic. Social critics may denounce this as a time of greed and selfishness, but in truth, our history is full of greed and selfishness.

But there is more than that in the American past. Just 32 years ago, in his great acceptance speech at the 1952 Democratic National Convention, Adlai Stevenson listed among the country's ills "materialism." That kind of concern -- and not the Jerry Falwell version -- is the Christian strain that is strongest in American history. We may be greedy and selfish, but periodically we also try to deal nobly and generously with our less fortunate countrymen. You have to wonder, at a time like this, when that spirit will return. Just now it seems overdue.