PRESIDENT CARTER set out to pacify the countryside over the weekend. Did he succeed? Probably not - historically speaking, such efforts generally fail. That is because central governments have no way of appeasing all the conflicting group and regional discontents that cause countrysides to need pacification in the first place. But they try. Thus, in a surreal three-day adventure, Mr. Carter sought to persuade an almost comically divergent range of Americans that his programs were not (as some seemed to think) a threat to their well-being - and the nation's. There were the white ethnics and the minority urban poor in Detroit, the farmers in Des Moines, the Air Force brass in Omaha, the water-conscious Westerners in Denver, the anxious Jewish supporters of Israel in Los Angeles. In fact, the Carter itinerary called to mind nothing so much as one of those old Hollywood wartime versions of the list of men who had volunteered for an especially dangerous mission - "Maguire, Costello, Wyzanski, Thompson, Goldberg . . . "

Still, for all its antic aspects, the Carter weekend flight-plan said a good deal about the nature of the Carter problem. If he is to accomplish any of the ambitious goals he has set for himself, from restoration of the nation's economic health to creation of a durable peace in the Middle East, the President must do more than merely try to allay the anxieties of a dozen different, competing constituencies. Rather, he must persuade each that there is a vital connection between its own welfare and a host of other problems that it probably considers irrelevant, diversionary or, at a minimum, somebody else's lookout.

One of the most moving appeals the President heard on his trip, for instance, was that of an unemployed black steelworker who said at the meeting in Detroit: "I don't feel much like talking about energy and foreign policy . . . I can't be too concerned about other things when I have a daughter to raise and I don't have a job and I am 56 years old." But the remark was poignant in more ways than the speaker knew. For energy and foreign-policy considerations - the worldwide disruption of old energy-production and consumption habits and all the political and economic effects that have followed both here and abroad - had more than a little to do with creating the unemployment of which the man is a victim.

Can Jimmy Carter explain that - and a multitude of other relationships that offer cold comfort to the disturbed or afflicted citizen? Is he even trying? People who are analyzing the President's leadership could do worse than to use this question as a measure: To what extent is the President merely reinforcing the prejudices and raising the false hopes of a variety of constituencies in his effort to regain his political strength - and to what extent is he leveling with them?

Superfically, anyhow, the answer would seem apparent from the goulash itinerary: The President was out playing pander-to-the-group politics.But what is wrong with that conclusion is, first, that it doesn't take account of what got Mr. Carter in trouble with so many constituencies in the first place. And that was an inclination to tempt the wrath of the political gods - whether on Middle East policy or water projects or the B-1, or Panama, for that matter, which drew its own hotel-door protesters along the way. Moreover, Mr. Carter, while sweet-talking the disaffected groups in certain respects, also dished out a fair share of hard, complicated and disagreeable truths, especially where the need for energy austerity was concerned.

Mr. Carter is reaching out to strengthen his political base, and there is always the possibility that he will do so at a price so high the political base won't be worth much in terms of getting tough things done - that the President will have compromised the tough ones away. Somehow, though, that just doesn't seem the Carter disposition; if anything we would figure the stiff-necked element in his personality to be the one that will prevail. The question is whether Mr. Carter's effort to repair the political damage he has sustained will ultimately help create the national constituency he so urgently needs - as distinct from merely sharpening competitive group and regional feelings he is trying to deal with now.