Vice President Walter F. Mondale has emerged over the last month as healer in the fratricidal Democratic Party and consensus choice of Democratic politicans to replace Jimmy Carter as nominee for president.

This revolt is passive, not active. It waxed a little when Cyrus Vance quit as secretary of state; it waned a little when Sen. Edmund Muskie replaced him. Mondale has absolutely no complicity in disloyalty to his chief, although his political aides know more about the ferment than they pretend. Its success, a very long shot, hinges on whether President Carter's decline can be stopped.

The private consensus within the party is that Carter probably cannot be salvaged and is, therefore, a probable loser to Republican Ronald Reagan. There is near-unanimous opinion, that the one man able to heal his party, bind together its Carter and Kennedy wings and defeat Reagan is Fritz Mondale.

Mondale's role as party savior stems from his barnstorming as surrogate for Carter without engaging in shrill invective against Sen. Edward Kennedy, a moderation that has lowered his esteem among the Carter political team lately. mWhile Kennedy himself resents Mondale as seller of a liberal birthright for a mess of Carter pottage, lesser Kennedyites nationwide acknowledge that their man cannot make it and that the vice president is the best alternative.

This has been the pervasive subject behind the scenes. Two separate sources report hearing Mondale's top aide, Richard Moe, talk confidentially about it (though Moe denied it to us). Other politicians have heard similar talk from Al Barkan, political action chief for the AFL-CIO.

Typical was conversation during a dinner party April 25 between three Democratic senators: Daniel Patrick Moynihan of New York, William Bradley of New Jersey and Abraham Ribicoff of Connecticut. Talk turned to Carter's low political estate and a possible non-Kennedy alternative. All agreed there is only one: Mondale. But how to do it? They were stumped.

There would be no chance unless Carter loses more big state primaries to Kennedy June 3 and falls embarrassingly behind Reagan in the polls. He then might lose a floor fight at Madison Square Garden to unbind his pledged delegates. If the convention found a non-Kennedy alternative.

The growing legion of covert Mondale men contains recruits who would surprise the White House. One influential back-room southern Democrat, long a Carterite, gave us his glum assessment that Carter can neither be stopped for the nomination nor elected in November. But if Carter could be stopped, would this Carterite be for Mondale? "In a minute, friend, in a minute," he replied. "So would a lot more of us."

Despite distaste toward Mondale in Kennedy's inner circle, Teddy's foot soldiers would gladly accept Fritz. Sonny Dogole, Philadelphia businessman and Democratic financial patron, backs Kennedy as the only available alternative to Carter. But Dogole, an old-time associate of Hubert Humphrey, would eagerly support Humphrey protege Mondale.

Dogole was among many potential Mondale backers attending the April 27 banquet of the Coalition for a Democratic Majority, a defense-oriented group deeply unhappy with Carter. But Mondale is also the favorite within the detente-oriented, anti-Carter Americans for Democratic Action, the antithesis of CDM. ADA loves Mondale for his dovishness; CDM accepts him, hoping his running mate would be Moynihan, CDM national cochairman.

Mondale bridges this gap because, after early Teddy-baiting in Iowa, he has avoided the escalating verbal excesses of the Carter-Kennedy fight. In his speeches just before Pennsylvania's April 22 primary was won by Kennedy, Mondale ignored orders to flail away against Kennedy in tune with Carter television commercials. "Fritz gave his standard Humphrey speech instead," a Carter operative grumbled.

The Carter team was also upset when Mondale insider Mike Berman, running Carter's campaign in Michigan, disregarded orders to push Sen. Donald Riegle aside as introducer of Mondale at the party dinner in Detroit April 12, two weeks before the state caucuses were won by Kennedy. Riegle proceeded to shred the Carter administration's economic policy. There was no overt rebuttal from Mondale.

None of this constitutes any break between the White House and the vice president, who has collaborated more congenially with his president than any predecessor in memory. It merely underlines Mondale's reluctance to tie himself into the straitjacket of the Carter problem now causing the party revolt. That is why more and more Democrats are covertly looking to him as their last best chance.