Jimmy Carter, in his first speech since leaving the White House, last night identified with Harry Truman, another president who left office with a low level of popularity, and urged a renewed national commitment to the human rights, nuclear disarmament and energy independency issues of his presidency.

Carter did not directly mention his successor, Ronald Reagan, or his policies in a speech prepared for delivery in Independence, Mo., where he accepted the Harry S. Truman Public Service Award. But he made a thinly veiled attack on the conservative mood that has gripped Washington and the nation since the November elections.

"Fringe political groups use scare tactics to intimidate those who disagree with them," the former president said. "And now there is a heightened skepticism about what government can or should accomplish.

"There are even those who argue that the main business of government should be to do nothing -- to abandon those who need help and to retreat from the field of poltical battle, especially on the most controversial issues," he added. "These are not new; for the time being they are only louder."

Carter joked briefly about his new life, saying, "Last year I came to agree with what Harry Truman said about being president: 'There is one thing about this job; there's no future in it.'

"Happily, I can report to you tonight that I like my new title, Private Citizen," he added, referring also to the title of Truman's autobiography. "I never thought this kind of extended vacation would be possible, but neither did I expect the election results that came last November."

Carter is the eighth recipient of the award given by Truman's home town each year on the anniversary of his birth in 1884. Truman died in 1972. His 92-year-old widow, Bess, is hospitalized in nearby Kansas City, recovering from hip surgery.

Other winners include Harry A. Kissinger in 1974, Leon Jaworski in 1975 and Hubert H. Humphrey in 1977.

Carter, the 39th president, said he never met Truman, the 33rd, but that he greatly admired him.

"As I walked the floors of the White House or worked in the Oval Office, I though many times that more of his proposals should have been adopted," he said. "Some of them could have saved me and our nation a lot of anguish."

He singled out a series of problems that had confronted both the Carter and Truman administrations: civil rights, nuclear disarmament, energy, the Mideast, inflation, the Soviet Union and tension between the liberal and conservative wings of the Democratic Party.

Truman, he said, had advocated human rights and nuclear disarmament in foreign policy, Carter policies deemphasized by the Reagan administration. i"Today the cause of human rights has taken on worldwide proportions, extending from Warsaw to San Salvador," the former president said. "It is not new issue, and it is not a dying issue."

Carter also dealt with another familiar theme from his presidency -- that there are inherent limits in what government can, and should do. The strong implication in much of what he said was that someday his administration, like Truman's, will be looked on more kindly than today.

Truman, he noted, had stood by the ideals of the Democratic Party. He considered people to be the nation's to use government for the public good, Carter said.

"He was proud of tight budgeting and the elimination of waste, but these goals were not considered ends in themselves," he said. "They merely permitted government to do a better job of what was right and what was necessary."

Since leaving Washington in January, Carter has spoken publicly in only one interview in March. The only speech he gave before last night was at a private meeting of upperclassman at Princeton Univesity March 18.