President Carter's political rivals spoke in generally supportive terms yesterday of the ill-fated effort to rescue the American hostages from Tehran, but many Democrats inside and outide the Carter camp were wary of the long-term political fallout from the event.

Detroit Mayor Coleman Young, leading the Carter effort in today's Michigan Democratic caucuses, typified the concern when he said, "We have gone to the point of no return . . . Unless the hostages are rescued, it's a no-win situation for Carter."

Except for independent candidate John B. Anderson, who questioned the timing and necessity of the dramatic airlift, Carter's rivals for the presidency declined to criticize his judgment in ordering the aborted mission.

Republican presidential candidate George Bush was most outspoken, saying, "I unequivocally support the president -- no ifs, ands or buts . . . He made a difficult, courageous decision."

In strikingly similar formal statements, which they declined to amplify, Republican front-runner Ronald Reagan and Democratic challenger Edward M. Kennedy expressed sympathy for the family of the eight men killed in the rescue effort, and pledged to preserve "national unity" in the cause of the hostages' release.

Their commments reflected what David Gergen, managing editor of Public Opinion magazine, said he expected to be a "short-term tendency to rally around the president." The White House said calls and telegrams were overwhelmingly supportive of the action Carter ordered, and supportive statements came from officials of past Republican administrations, including former president Nixon and former secretary of state Henry A. Kissinger.

But the rescue effort divided Carter from many congressional Democrats, who complained of lack of consultation, and stirred fear among the president's political supporters that the failure of the mission might -- as Gergen said -- "feed the incompetence issue inregard to Carter."

Gergen was speaking from the perspective of a former Ford's administration official, but NBC News public opinion analyst Richard Scammon, a veteran of prior Democratic administrations, expressed a similar view.

"The first reaction," Scammon said, "is likely to be that the guy has botched up another one -- that he can't walk the dog and come back with the same animal."

Actually, the first reaction in the political community was one of shock. A western Democratic governor who heard the first report on his car radio said, "I called my press secretary as soon as I got home to ask him to check the Associated Press to see if it was a hoax. I couldn't believe Carter would do something like this."

Opinion polls have measured a growing public impatience for action to resolve the almost six-month-old crisis. A national poll by The Washington Post, taken April 9 to 13 and published last Sunday, showed a 55 to 30 percent majority favoring "military action" if the hostages were not released by a stated deadline. Last January, the military option had been rejected by 51 to 38 in a similar Post poll.

But the event differed from the hypothetical poll question in two important respects: It came without warning to the Iranians, America's allies, congressional leaders or the public, and it failed in its objective of freeing the hostages.

The political result -- in many instances -- was consternation and renewed questioning of Carter's competence, the same kind of questioning that dragged Carter's polls to historic lows just before the hostage crisis began last Nov. 4.

An aide to New Orleans Mayor Ernest N. Morial said, "The mayor had breakfast this morning with a group of business leaders and they were appalled at the ineptness of it, and couldn't understand why he was doing it now. . . . I think he's really hurt himself."

A Democratic official in Augusta, Maine, said, "Everything I hear around the statehouse is that it was a bad judgment call . . . a bad imitation of the Bay of Pigs."

Students of public opinion like Gergen noted that the 1961 Bay of Pigs fiasco actually boosted John F. Kennedy in the polls -- at least temporarily. Kennedy climbed from 78 percent approval in early April 1961 to 83 percent approval, following the failure of the effort in "Liberate" Cuba from Castro, and then saw his popularity gradually decline.

But Kennedy was a brand-new president, whose competence had not previously been questioned. Carter, by contrast, is a president who, until the Iran crisis developed, was subject to increasing doubts about his ability to handle the job.

Almost every poll taken since November has shown voters' attitudes toward the president's renomination and reelection are linked closely to the rating they gave him on the handling of the hostage crisis.

In The Post's national poll, for example, voters showed they would cross party lines in large numbers to support the candidate they thought would do a better job on the hostage crisis. Democrats who thought Reagan would do a better job on that issue than Carter said by 3 to 1 they would vote for the Republican, and Republicans who thought Reagan less capable than Carter of getting the hostages back favored Carter by 7 to 3.

The issues also cuts significantly in the Carter-Kennedy rivalry for the Democratic nomination. The Post survey of Democratic voters in last Tuesday's Pennsylvania primary, found the president got 86 percent of the votes of those who believed he would handle Iran better than Kennedy, but only 15 percent of the votes of those who thought Kennedy would do a better job on Iran.

Reagan and Kennedy did nothing to foreclose future criticism of the Iranian venture, but their formal statements -- similar in tone and language -- deferred to the mood of the day.

Before breaking off his Michigan campaigning to return to Washington, Kennedy said, "I share the feeling of all Americans at this sad moment for our country . . . Whatever our other differences, we are one nation in our commitment to the hostages, our concern for their families, and our sorrow for the brave men who gave their lives trying to rescue their fellow citizens." f

A few hours later, Reagan told a Los Angeles press conference, "This is a difficult day for all of us Americans . . . It is time for us . . . to stand united. It is a day for quiet reflection . . . when words should be few and confined essentially to our prayers."

Independent candidate Anderson took a different tack in an interview with The Post. He said he was "shocked" at Carter's decision to attempt a military rescue. He said it would "tear the fabric of Western [allied] unity a little more . . . and etch the portrait a little deeper of a man who doesn't know how to do the right thing at the right time."

Another independent candidate, Citizens' Party nominee Barry Commoner, charged that Carter "has imperiled the lives of the . . . hostages . . . and pushed the world perilously close to a nuclear war."

Rep. Henry S. Reuss (D-Wis.), a Kennedy backer, said Carter should end his bid for renomination and "quietly serve out his term without any more impulsive actions." And Charles Ward, Arkansas' Democratic national committeeman, said he "could see the day coming when Jimmy Carter, like Lyndon Johnson in his time, decides not to run and just to devote himself to the problem at hand."