The president has left the Rose Garden, and is out delivering the good news. In Philadelphia Friday, on his first foray, he noted that the latest inflation news wasn't as bad as it has been: "I have been very pleased lately at the trend in interest rates and the good news we had this morning on the producer price index." Prices had gone up, but not as sharply as in previous months. Thus, his happy report.

Even before ending his self-imposed isolation in the White House, the president had been accentuating the positive. He spoke of the failed Iranian rescue mission in terms of limited success and, amid all the gloomy economics trends, saw us turning the corner in the battle against the inflation.

The Happy Warrior, circa 1980: for Jimmy Carter optimism becomes the hallmark.

Nothing could be more welcome to Americans today. People desperately want to believe problems are manageable, and that the country can look forward to a period of stability. They cling to any sign of hope; they seek reassurance. Tell us, they will say, that things aren't as bad as they seem. Give us reason to think improvement stands around the corner.

Carter's current approach to public concerns -- far different from the tone he struck last summer in his "malaise of the spirit" speech to the nation -- certainly carries the message people want to hear. The trouble is, they don't really believe it. There lies not only a political problem for the president, but a greater one for the nation.

In traveling to some 15 cities in every section of the country the last four weeks, the dominant impression is of a public concerned about events and increasingly fearful about the future. People everywhere express the feeling that things are coming apart. They are aprehensively, and seem closer to approaching the dispirited state of mind about America that permeated the country during the poisonous years of Vietnam and Watergate. Gone are the hopes for a new national era of harmony and progress that greeted the Carter administration less than four years ago.

These, it should be emphasized, are personal impressions not backed by solid research opinion data. But other new and compelling evidence exists that national attitudes are as bad -- or worse -- than reported here.

"I knew it was bad out there," says Peter D. Hart, one of the nation's leading pollsters, after examining just-completed survey opinion data from a major industrial state.

"But I never knew just how desperate it is. The word I keep getting back is 'scared.'"

The Hart organization began by asking a deceptively simply question of registered voters throughout that state: "How would you describe your feelings about the way things are going in America? What kinds of words or phrases best describe your feelings?"

From that point, people volunteered overwhelmingly negative responses. Fully 90 percent of the answers were in that category, with citizens voicing emotions ranging from hostility and anger to fear and frustration. Even those in the 10 percent minority who had positive things to say were essentially defensive -- the "you can't expect too much," to "well, things are bound to improve" types of remarks.

And it seems not to matter what background the citizen represents. White or black, liberal or conservative, professional or clerical, the words uttered sound strikingly similar:

"It's a mess in every way," said a woman Western Union operator, over 65, who calls herself a conservative. "In every way -- jobs, inflation -- you name it. It's just a mess."

A male engineer in the midpoint of his career, who classifies himself as a political moderate, said: "A fine mess we are in . . . My god, how did we get into this mess?"

To a middle-aged attorney who thinks of himself as a liberal, "The basic fabric of society has broken down. There is no sense of community. Each individual is looking out for himself."

The idea of conditions going out of control dominates virtually all the interviews. Two people, in particularly, succinctly and unwittingly spoke for the rest. "America is in big trouble," was the way a young man, a realtor and a conservative, put it. A teacher, black and a moderate, said she was worried. "I'm kind of scared of what's happening to America," she said. "I don't know what's going to happen."

The Hart organization asked people about two other broad areas of general concern -- issues and the way government was handling them. Again, the outcome was gloomy -- and similar. Inflation, bad leaders, and a weak foreign policy topped the issues, while a lack od leadership and a need for stronger better leaders headed the concerns expressed about government's ability to handle the problems.

At this point, the first presidential election of the 1980s stands six months away. The Hart findings, when matched with other national samplings, add up to a dispiriting nation mood. A great deal of pent-up frustration and emotion exists. It appears to be intensifying. Politically, the situation is combustible. While people desperately want good news, it will take more than optimistic words to give them cheer.

A personal note: two weeks ago in this space I commented on the failed rescue mission and said President Carter had sent Americans "to die ignominiously in the desert." A thoughtful reader writes: "The president did not send the American soldiers to die in the desert but rather attempt to save their countrymen. The fact that they did lose their lives so early on in the rescue attempt was the result of an accident and was surely not something intended by the president of the United States. Furthermore, whether one agrees with the wisdom of the rescue attempt or not, I cannot believe that you really think that giving one's life for one's countrymen, and countrywomen, is ignominious."

I entirely agree, and deeply regret using such ill-considered language.