Jimmy Carter and Walter Mondale ate the dessert first. The cutting, ridiculing attacks on Ronald Reagan -- that's the easy part, the frothy confection. It's not the expected, essential main course. Last Thursday night's speeches by the president and the vice president seemed to us in that regard disappointing, "off," and -- if they are a sign of things to come -- alarming.

Is this going to be an exercise in demagoguery, scaring, distorting and the rest of that disreputable, irrelevant and (ultimately) tiresome crowd? Was the vice president's attempt to recapture the resonance of Hubert Humphrey's great and timely speech in Atlantic City 16 years ago evidence that the Carter-Mondale team is going to try to recreate the Ronald Reagan of 1980 as the Barry Goldwater of 1964? The innuendo, the loaded language suggested that they are, that the point is to paint Mr. Reagan as the mad bomber. If this is true, it is a terrible plan.

Most assuredly Ronald Reagan's record and a collected bedside anthology of his obiter dicta are fair game for the unfriendly scrutiny the Democrats have in mind for them. But there was something premature, frantic and lacking in self-confidence about the hollerings of Thursday night in Madison Square Garden. It was as if the Democrats were so unconvinced of their own power to attract or persuade that they had decided to try to paint their opposition, in ever more terrifying hues and contours, as a monster. Given that Mr. Reagan has set out to make Jimmy Carter personally the butt and central point of the campaign, none of this bodes very well for fulfillment of both candidates' high-minded assertions that they will deal in issues, not in personalities.

Our problem with the Carter-Mondale summing up on Thursday night is this: they have a better and more interesting case to make than the one they broadcast. This will strike you as weird since the oratory, when it wasn't trying to get people terrified of Ronald Reagan, was really one long tooting of the administration horn. But the case made -- even though it was interspersed with acknowledgements that being in the White House is complicated, trying and bount to provide its disappointments and failures -- was a kind of unpersuasive one-note tune: it did not really differentiate success from failure or important from less important. Everything had gone relatively well, everything was going to be fine.

Jimmy Carter has come into office and Ronald Reagan seeks to achieve it at a distinctively troublesome and dangerous time in American history.The country -- and that means its citizens, its wisemen, its political leaders -- does not know how to deal with a skyrocketing of oil and energy prices that has had a distorting and terrifyine effect on the national economy and a transforming effect on our relations abroad, altering dramatically the way we must define and defend our national security.

The impact is everywhere felt. It is reflected in the domestic argument over fiscal stimulus, so-called "reindustrialization," what the society owes its old and its poor, what it owes its middle-class wage-earners. It is reflected in the confusion over the American defense role vis a vis not just the Russians now, but also their various chums and agents and clients hovering around the oil fields of the Gulf that are important to our well-being and crucial to that of our European allies. And when we tire of thinking about these things we can think about the great tides of political refugees and economically displaced persons that are now on the move in Mexico, in Southeast Asia, and elsewhere -- migrations that (maddeningly) challenge at once and to contradictory effect our economic stability and our traditional humane values.

Neither the Congress nor the political parties nor the society as a whole has been much help in either forseeing all this turmoil or in helping to fashion a reasonable response to any aspect of it. The executive branch and the ossified and overelaborate structure of statutes and regulations it lives by have not done much better. And the good Lord knows neither of the political parties in the writing of their scripture this year has added a lot. So why should a president be better or different from the rest? Because, like Mount Everest, he's there. And it's what he's paid for. It's not to expect perfection or the impossible to say merely that what one judges Jimmy Carter and his party against is his/their ability to make a dent in this imposing, solid wall of national perplexities and trouble.

This is also the standard against which Ronald Reagan & Co. must be measured prospectively -- and in comparison with the record of Mr. Carter's first four years. Actually, in many respects the Carter administration can make a fairly good case for its seriousness in identifying and addressing these challenges to the country and to the country's familiar way of looking at things. It is not a sterling case. And it is surely different from that isn't-he-great-and-brave-and-wonderful pitch we heard the other night. It is modest, but it is real. Maybe this case does and maybe it doesn't deserve to prevail in the coming election. But of this much we are certain: Jimmy Carter can no way win the important, central argument of the election, if, in his eagerness to savage Ronald Reagan, he declines even to make it.