SALEM, Mass-Former President Jimmy Carter, speaking the day after his Vice President suffered a massive political defeat, said Walter F. Mondale would have fared better against President Reagan if he had not promised to raise taxes, but added that no Democrat could have won this year.

Carter, in an appearance at Salem State College, called Reagan's victory a "personal mandate" and cited Democratic gains yesterday in the Senate as evidence that the country is not undergoing a conservative realignment.

More than 1000-some of them sporting blue Carter-Mondale pins from 1980-packed a basketball court in this North Shore campus to hear the man Reagan and many Democrats have used as a whipping post for the failures of the '70s.

Carter, who acknowledged widespread criticism of his handling, of the Iran hostage crisis, put up a spirited defense for his presidential legacy, emphasizing arms control successes, the Camp David accords and human rights improvements in South America, where on a recent tour he received a hero's welcome.

The former Georgia governor conceded that he was a liability for Mondale in this election, but said it is not customary for presidents to actively campaign after they leave office. "Fritz Mondale and I quite early in this campaign decided that the American people did not want to see me out in the forefront of this campaign saying, 'Endorse my former Vice President,'" Carter said.

Carter predicted that an Democratic outsider would emerge in 1988 to lead the party to victory, much as he did in 1976. But he added that he would not make another attempt at the presidency and ruled out the possibility of a new run for the White House by Sen Edward M. Kennedy '54 (D. Mass.), his rival for the Democratic nomination in 1980.

In a brief interview after the speech, Carter said that newly elected Senator and current Gov. Jhon D. Rocketeller IV of West Virgina, Sen. Bill Bradley (D.N.J.), and Sen. Sam Nunn(D.Ga) would all be strong presidential contenders four years from now.

Carter found time during his 85 minute presentation to joke about the lack of respect he has received since returning to Plains, Ga With a nod to Rodney Dangerfield. Carter spoke of a Trivial Pursuit question recently posed to him: "Do you know who said. When I look at my children I wished I had remained a virgin" After brief applause, Carter said. "I he answer was my mother.