FOUR YEARS ago, in what must have been one of the most churlishly written and unenthusiastic editorial statements in modern history, this newspaper came out in favor of Jimmy Carter over Ronald Reagan. This year we endorse Walter Mondale -- enthusiastically and without apology. We think Mr. Mondale -- who has been maddeningly misread and mistreated by the political trendmakers this year, just as Mr. Reagan has been maddeningly indulged and overpraised -- is unambiguously the better candidate.

The president and his opponent do have some things in common. Both of their parties, both of their constituencies and both of their running mates need work. As the political season wore on, it was hard to tell which was the more revolting spectacle: that of the vindictive, yahoo Republican right plus its assorted fat cats doing their ineffable thing in Dallas or the self-obsessed and spoils-seeking constituent elements of the Democratic Party treating the whole process of electing a president as a fight for position for themselves at the expense of all else -- all else most notably including the candidate and his chances of winning, not to mention his chances of being able to govern if he did.

Neither man has shown himself particularly forceful at taming his rowdies. Ronald Reagan's second term would see their emergence as an even stronger force than they already are as the bloodletting over the succession gets under way in earnest. Walter Mondale would have to show in a first term that he was not in thrall to the various cultural, ethnic and economic lobbies he tried to secure to get the nomination.

So far as their vice-presidential choices are concerned, both are running with candidates for whom there is much to be said, but not, by a long way, everything. Mr. Mondale's selection of the first female to run on a major party's national ticket was audacious and commendable, and Geraldine Ferraro has demonstrated many of the virtues indispensable to the job she could inherit at a moment's notice: she is smart, strong and resourceful. She also has much to learn about the conduct of foreign and international security affairs. She does not have a feel for that whole collection of transactions and relationships, and it shows, often very unfortunately, when she speaks.

Something else shows when George Bush speaks -- something that threatens to trash whatever esteem his impressive r,esum,e and his private personal grace have earned him. Maybe it is just that he is a rotten campaigner (winning elections, after all, has never been his forte). But he seems to reveal himself, as all viewers of "Dallas" will long since have noticed, as the Cliff Barnes of American politics -- blustering, opportunistic, craven and hopelessly ineffective all at once. This impression has been so widely remarked in recent weeks by commentators of every political persuasion that it hardly needs elaboration. We add only that if this is the real George Bush, as opposed to the non-campaigning one, it hardly bodes well for his capacity to be an effective president himself.

WE DO NOT find ourselves among those who, with considerable chagrin, feel obliged to express their amazement that Mr. Reagan turned out not to be the personally vicious monster of their imagination and that his government has done some much needed things. The real Ronald Reagan and what was attractive about him had become very evident to us in the course of the last campaign, and so had the weaknesses of much of the thought then prevailing in Democratic circles, so that his accomplishments in office and the degree to which he has effected a desirable national course correction do not come as a big surprise. We thought -- and think -- there was something to be said for improving the condition of the nation's defense establishment, for rejecting the empty sentimentality that sometimes infects liberaldom's approach to foreign policy, for getting really tough with profligate, pointless federal spending. But for several reasons Mr. Reagan's particular achievements in these areas do not seem to us to warrant his reelection.

One is that his administration, minus the push-pull effect of Democratic and Republican cross-pressures, would have been an unmitigated disaster in many areas where it has succeeded. The Democrats are more realistic and sensible these days thanks largely to the influence of Mr. Reagan. But without their comparable influence on his government's actions on questions like human rights and domestic fairness and a number of others, his policies, from Central America to your local disability payments office, would have been calamitous. And some of them actually are calamitous. His government has been grossly indifferent to the requirements of racial equity and the needs of the poor. It was so bad on environmental questions that, mercifully, its efforts backfired. To get its way on large economic and foreign policy programs that affront the crazy right it pays a price -- tribute, really -- in social program and civil liberties coin, tossing the crazies all manner of proposed constitutional amendments, regulatory restrictions, violations of individual privacy and freedom.

So we conclude that much of the Reagan administration accomplishment has come very dear -- and most important of all, its two principal claimed accomplishments, one foreign, the other economic, seem questionable to us, or at least greatly overstated. Take the foreign first. We do admire the manner in which this administration managed the confrontation over the European missiles in the first part of its term. That was its most important foreign policy success, though there have been others along with the failures. But in what sense is America "standing tall"? We believe the defense establishment did need bolstering, but what has occurred seems to us indiscriminate, helter-skelter and in some respects as phony as it is costly. Unrestricted money and discretion are not an answer to this country's defense needs. Within the administration the level of infighting over this and other national security issues as a reflection of policy disagreement and impasse has surpassed even that of the Brzezinski-Vance hate-affair or other struggles that come to mind.

In fact there has been an uncommon amount of turnover and turmoil in the national security apparatus of the Reagan administration and an uncommon amount of implacable enmity. No one ever said such terrible things about William Clark when he was White House national security aide or Caspar Weinberger or Richard Perle or Jeane Kirkpatrick or William Casey or Richard Allen or Alexander Haig as were said about them by other high administration officials. We respect many of the people conducting foreign policy in this administration, most notably Secretary of State Shultz, but nonetheless observe that the president has yet to permit or encourage the establishment of a steady, credible administration foreign and defense policy effort. His approach to arms control efforts has been fitful and temperamental and unyielding of achievement. He has proved no more skillful in the Middle East than Jimmy Carter was in the Persian Gulf. And his better people are still not in the clear. This is the administration that appointed a score of ambassadors who didn't know what was wrong with issuing a political statement in support of Jesse Helms's campaign.

THEN THERE IS the economy. Mr. Reagan emphasizes, as well he might, the dramatic drop in inflation and the current prosperity. These are wholly welcome developments. But it needs to be asked to what extent that drop in inflation was the result of a severe recession, which brought the highest unemployment since 1940. And how much may the current prosperity be owed to gigantic budget deficits? Things are going very well at the moment, but the economy is a little like the odd spring weather we are experiencing in this autumnal season. It is very agreeable, but the air is filled with hints of something else about to come.

The signs of profound economic instability are getting clearer. The dollar is far overvalued. The budget deficit is now compounding, as the Treasury borrows to pay interest on past borrowing. American standards of living are being raised by the enormous amounts of foreign money currently pouring into this country, but that won't last forever. Within a year, this country will have a bigger foreign debt than Brazil or Mexico does.

Mr. Reagan smiles, shrugs and says that high economic growth will close the deficit. That's one thing that certainly won't happen. But the president, by all the evidence, genuinely does not understand the instability into which he has led the American economy. He sticks with a few familiar and simple thoughts about incentives, hard work and the desirability of low taxes, even though there is nothing simple about this economy or the way the international capital flows are influencing it. And the Reagan administration is poorly equipped to deal with any sort of a crisis in this area. The president has given too many of the key jobs in financial and economic policy to political cheerleaders -- the economic and moral equivalent of those cheerleading ambassadors.

And what about the opposition? What about the Democrats' capacity to deal with these things? Mr. Mondale, unlike the president, has talked about the danger signs with candor and intelligence. Would he, as president, be able to carry out the cures that, as candidate, he has prescribed? Maybe not. To get a large tax increase through Congress would be an extraordinary feat in the best of circumstances. If the economy were to start sliding into another recession, it would be impossible. Mr. Mondale might then struggle to hold down unemployment by resorting to the protectionist legislation that he has -- wrongly and inexcusably -- embraced. But Mr. Mondale's strength is that he understands the risks here and he is willing to talk openly about them and to take some political risks of his own in order to get people thinking reasonably about them.

IN SOME measure, both presidential candidates have been victims of their campaigns. The president's too easy slide to glory this time around has accentuated all those elements of detached smugness and superficiality that most mar his administration. He is praised for restoring values, but these values now have been reduced to slogans and propaganda. Mr. Mondale too has paid -- for the slogging fight over the past couple of years against a broad array of competition to become his party's nominee. He bought some profoundly flawed psitions -- the freeze, which he is now, blessedly, applying the requisite qualifications to, and a variety of protectionist stands. But in contrast to his opponent he has been serious, straightforward and genuinely engaged in the issues that the next president will have to deal with. He has, in the course of this phase of the campaign and, to some extent during the primary races, put some distance between himself and the impractical, muzzy-headed approach to foreign and security matters that so many in his party are suckers for. And where he erred in this direction earlier he seems to be moving back to stronger positions now.

Then there is Mondale the man. His record going back over the years demonstrates social and personal values that are the living embodiment of what the Reagan administration in its values pitch talks about. He is a decent man and a diligent, hard-working one who has been a good Democratic leader before this year and, notably, in this campaign in which he has evidenced strength and determination and a concern for others when he would have been justified in a descent into self-pity. And although we have noted the push- pull benefits on Democrats like Mr. Mondale of the Republicans' better instincts and efforts, there are certain basic truths that he early and always understood -- in particular those concerning the imperatives of racial justice and fair treatment for the poor.

A few years back it was fashionable to put down Gerald Ford with the patronizing statement that he was, of course, "decent, but. . ." and here a whole host of other considerations were brought into play. Was decency, then, such a marginal, dismissible attribute in a president? Why was it being talked about like a fringe? We don't know, but we hear something similar in the air today. Walter Mondale, it is said, is earnest, serious, a political fool for acknowledging the necessity of a tax hike, a guy who will bore your ear off talking about the issues, nothing like some of his flashier primary season competition or his entertainment-minded competitor in the White House. We say good. We say this is a serious, steady, bright, decent, qualified man who wants to be president and who should be.