A COMMON OBSERVATION made by Walter Mondale and his Democratic supporters during the election campaign was that Americans agreed with them on the issues but voted for Ronald Reagan because of his leadership and success in turning the economy around.

But this notion is wrong. The Democratic Party has lost touch with the mood of the American people, as the polling data from the election campaign just ended makes abundantly clear. This data showed that on "gut" issues such as welfare, aid for blacks, government waste and Central America, the public was closer to Reagan than Mondale.

The lesson to the Democrats is clear: The party that starts by appealing primarily to the special interests of blacks, working women, the elderly and union leaders is poorly placed to reach out to other minorities and white working men, without whose support election is virtually impossible.

Two pieces of neglected data illustrate the plight of the Democratic Party today: In 10 presidential elections since the death of Franklin Delano Roosevelt, the Democratic candidate has only once (in 1964) received more than 50 percent of the white vote; and in the five elections since Lyndon B. Johnson's landslide, only one Democrat (Jimmy Carter in 1976) captured more than 40 percent.

Last Tuesday, only 36 percent of white voters chose Mondale. In parts of the deep South, less than 10 percent of whites went for the Democrat. But this is not just a Southern problem. All across the country the new competitive spirit and the renewed sense of patriotism present stumbling blocks for Democrats. A party that can cheer a nominee who implies that "decency" and "self-interest" are incompatible ("I'd rather lose a campaign on decency than win a campaign on self-interest") -- a party that is ambivalent about international assertiveness and competition -- is in a poor position to capture the White House.

Walter Mondale got his message across this year. His problem was that his message was rejected. Never in the six presidential elections on which I have done research have voters divided as clearly by issue and candidate.

This fall, after four years of Democratic attacks on the unfairness and pain of Reagonomics, the CBS/New York Times poll asked registered voters which concerned them most: families not receiving enough welfare to get by, or families receiving more welfare than they needed. By 2-1, respondents said they were more concerned about families getting more welfare than they needed. Those who said they were more concerned with excess welfare payments favored Reagan by 3-1. Those concerned about the welfare poor gave a slight edge to Mondale.

When asked in a different CBS/New York Times poll whether the government should do more to help blacks or whether the government had done enough or too much to help them, 62 percent of white voters said the government had done enough or too much. These voters were for Ronald Reagan by 68-20.

The same poll showed an even split on whether there are any groups in this country without a fair economic chance. Those who said there are groups without such a fair chance supported Mondale 46-42; those who felt there was no economic discrimination backed Reagan 66-21.

When asked whether there is more waste in the defense budget or the welfare budget, voters also split almost evenly. Given the 5-1 differences in the sizes of the two budgets, that alone suggests something of the mood in the country. Not surprisingly, the group that felt there was more waste in the defense budget gave a slight edge to Mondale. Those believing that there was more waste in welfare preferred Reagan 70-20.

Foreign policy questions produced similar splits. When asked whether they were more concerned about American involvement in a Central American war or a communist takeover in the region, voters by 50-40 were more worried about a communist takeover. Voters who worried more about war preferred Mondale 50-40; those who were more concerned about a communist takeover voted for Reagan by 70-20.

The differences between the two voting coalitions extend to views about the American future. When asked whether the outlook for the next generation was as good as for this one, or whether the next generation would be bogged down in problems, the public again split into roughly equal groups. The pessimists who thought the next generation would be mired in problems voted for Mondale 53-31; the optimists chose Reagan 78- 14.

We are looking here at a fundamental ideological change in America. It may or may not signify a permanent party realignment. However, it surely signifies that no party, whatever it is called, can afford to ignore this shift as the Democrats have tended to do.

Party identification figures already reflect a major shift. A plurality of white men are now Republicans, and there are as many independents as Democrats among white males. The two most rapidly vanishing political species are white male liberals and white male Protestant Democrats. The proportion of white males identifying themselves as liberals has fallen to below 20 percent nationwide. Nearly three times as many consider themselves conservatives. Among white male Protestants, the presidential vote this year was 74-26 for Reagan.

It would not be inaccurate to say that the party is rapidly becoming the party of declining industries, those who have fallen behind in economic competition and pessimists -- which is painfully close to the way Ronald Reagan has been portraying the party all year.

The Democratic Party is nearing intellectual bankruptcy on the major issues of the day; it does not offer any coherent vision to the electorate. On issues affecting blacks, women and labor unions -- now the center of the party -- Democrats are in the minority and are unable either to convincingly defend their positions or to change them.

The one notable exception to the exodus from the Democratic Party, is, of course, working women. This is not an entirely positive portent, however. Women are far less supportive of economic competition and entrepreneurial risk taking than men. Thus, taking positions that appeal to them could put the party farther from the rest of the electorate.

In recent CBS/New York Times polls, women were less likely than men to believe in the Horatio Alger myth of upward mobility through hard work. And women were less supportive than men of merit pay for teachers.

But the spirit of the times is competitive and harsh. As early as 1981, both women and men believed that Reaganomics would hurt the poor more than any other group. Women opposed the program on those grounds; but men supported it as necessary for recovery. The GOP can brag that it was firm enough to administer bitter but necessary medicine; the Democrats attacked the medicine as bitter without advocating any credible, but less-bitter medicine. For many Americans, particularly men, this leaves the Democrats as the party of complainers.

An example of the Democratic dilemma is the controversy over comparable pay for comparable work, in which the pay of secretaries and other mostly-female occupations would be adjusted to equal the pay of supposedly similar, mostly-male occupations. It is virtually impossible for the Democratic Party to endorse the principle of "comparable worth" while espousing the entrepreneurial spirit of the times.

Comparable pay for comparable work is a banner that has a wonderful initial appeal to politicians within the party solicitous of the woman's vote. But it is a proposition with which the party is likely to have far more trouble than it ever did with busing or affirmative acton.

What kind of a committee is going to develop the rules for deciding the pay differences between various jobs? Who will appoint the committee that decides the pay differentials of a president and a vice president? Of a foreman and a computer programmer? Of a bartender and a room clerk? Even if the courts step in, the Democrats will not be off the hook any more than they were with court-ordered busing of school children.

Thus, the Democrats are rushing to a cause without adequate thought for the intellectual content, let alone political ramifications, behind it.

If the party faces a dilemma with women, the problem is even more acute with blacks. The Democrats owe Sen. Daniel Patrick Moynihan (D-N.Y.) a major apology for the shabby way he was treated when he tried to raise serious questions about the government's approach to welfare and racial minorities. When Moynihan suggested framing government programs to help the poor rather than the black, he was called insensitive and a racist. Today, can anyone doubt that the animosity toward welfare is related to the perception that these programs are for members of a separate race?

When Moynihan earlier wrote of the negative incentives built into the welfare system and their perverse consequences for black families, he was accused of "blaming the victim" and treated as a pariah. Today it is taken for granted that he was right but there is still no public discussion by white Democratic politicians of what to do. Democratic politicians are still talking about programs for blacks in moral terms alone. It is not considered moral to waste money in tough times. There must be discussion of results and what can be done.

Democrats cannot pretend that their commitment to blacks is accepted by all. Such programs are a commitment that the party must bear and justify publicly. Public silence on this difficult and heart-wrenching subject does not combat the private mutterings of racists. Silence by persons of good will and conscience makes the problem worse.

The problem is not only among whites. The Democratic Party has, in effect, made blacks the nation's designated minority. Other minorities are uncomfortable when they are lumped too closely with blacks. Jesse Jackson typically received less than 10 percent of the Hispanic vote in this year's primaries. And the new Asian-American immigrants don't want to make it through affirmative action, with the stigma that implies. They want to make it on their own.

Only when the Democratic Party can recast the choice as "tough and fair" (the Democratic approach) versus "tough and callous" (the Republican) will they be able to defend their position. Ronald Reagan has campaigned against welfare waste since his first ran for governor and he was able to mitigate successfully the charges of meanness by talking of waste and abuse. Without any response from Democrats he was able in 1980 to imply that there was enough waste in the welfare budget to cover the increased expenditures for defense, even though this was ludicrous on the face of it, given the relative sizes of the two budgets.

Gary Hart really had two new ideas for a Democrat in the primaries this year: stay away from blacks; and stay away from unions. Hart campaigned as the high tech "Atari Democrat." For the Democrats, however, Atari-ism presents a fundamental problem: For over a decade they have been the party of people who are afraid of what computers will do to their jobs.

Computers symbolize all the problems the party will have developing a plan for modernizing the country. While to neo-liberals such as Hart computers represent the future, to the rank and file Democrats they are a threat. To the minorities, high tech represents machines and highly-trained technocrats replacing semi-skilled labor. To women, they represent technology replacing human services and to unions they represent a threat to the structured workplace they need to survive. The AFL-CIO has gone on record in opposition to workers doing computer work from their homes. Yet the electronic cottage opposed by key elements within the Democratic Party symbolizes the future for many young people.

There is an old saying that facts don't beat a theory; only another theory can. To make effective presidential inroads, the Democrats must offer a vision of the future that is more credible and has less flaws than Reaganomics. But the Democrats have mainly pandered to the narrowest interests of their own constituencies.

It is, of course, always possible that the Democrats could win back power on the basis of Republican mistakes -- the political equivalent of a turnover in football. But the Republicans now have the ball. For the Democrats to capitalize they will have to rise above their interest groups and articulate a way to combine decency and self-interest, nuclear responsibility and self-assertiveness.

Above all, the Democrats will have to nominate a man who, when he says "we," will be able to convince white men that he includes them too. In the context of the '80s such a candidate might have to be a Vietnam veteran, or someone too old to have dodged the draft. Only such a candidate will appeal both to the Democratic Party's new core of blacks and working women and to white men who espouse the new patriotism and extol the competitive spirit.