On Tuesday a week ago, when President Carter convened the most important Cabinet meeting of his presidency and stunned world capitals with his call for mass resignations, Vice President Mondale was in Manhattan, Kan.

On Wednesday a week ago, when President Carter privately fired the first Cabinet member of his presidency, Mondale's friend, Joseph A. Califano Jr., Vice President Mondale was in Sioux Falls, S.D.

On Thursday a week ago, when President Carter made public the firings of Califano and W. Michael Blumental and was in turn shaken by the public mutiny of Brock Adams, Vice President Mondale was in Philadelphia.

On Friday a week ago, when President Carter lashed out that Mondale's friend, Califano, was lying about the reasons given for his firing and when Califano retorted that it was Carter who was putting out untruths, Vice President Mondale was in Switzerland.

During the most important week in Carter's presidency, the vice president, who Carter once called "my chief staff person," was out on the circuit, selling SALT II.

"The vice president was informed in a general way of what was happening," says the vice president's press secretary, Albert Eisele. He chooses his words carefully, for he means just what he says.The vice president was merely informed.

The vice president did not know, when he set out to sell SALT II on Sunday, July 15, that the president would be convening his extraordinary Cabinet meeting the following Tuesday, according to a source close to the vice president.

The vice president did not know that the president had decided to call for the mass resignations of everyone who was anyone, according to this source.

And the vice president did not know that the president was going to turn his Cabinet shakeup into something more by publicly airing traditionally unmentionable laundry, in this case, putting out the public word that Califano was lying about what the president told him on the day Califano was fired.

According to this source, Mondale was informed of the mass resignations after the Cabinet meeting had adjourned, in a telephone call from the White House.

Before he had left on his trip, Mondale had been aware that the idea of mass resignations was an option the president was considering, the source said. It was viewed as one way of dramatizing the new-broom era of the Carter presidency.

But Mondale had not been told that Carter had decided to go the mass resignation route, nor that Carter would act so swiftly in Mondale's absence. Mondale got the word just about when the rest of the world did. That was just before foreign confidence in Carter started to fade and the value of the dollar again started to fall as people in parliamentary systems around the world predictably interpreted the resignations to mean that the U.S. government was falling, not that the U.S. government was being saved. (During the week, according to the Mondale source, the vice president spoke by telephone perhaps a couple of times with the president, and somewhat more often than that with Hamilton Jordon, in calls that "informed" Mondale of what was happening.)

So "chief staff person" Fritz Mondale was apparently the insider who was out, having little to do with Carter's Cabinet shakeup or with the controversial way it was done.

And if that is what the public thinks, that is clearly just fine with Mondale. For he is in the process of trying to put as much distance between himself and the Carter Cabinet shakeup as possible.

Once an accessable fellow, he has taken himself into hiding, refusing to discuss anything having to do with the events that happened while he was out of town.

And the vice president and his advisers were among the first to count the blessings of being out on the road.

"Had we been here, we would have been taking phone calls on it every 10 minutes," says one source close to Mondale.

There would have been calls of complaint and consternation from Mondale's former colleagues in Congress, and his onetime political allies now scattered through establishment Washington.

He surely would have been dragged into the case of Carter vs. Califano, the source says. And, he adds, "It would have been a lot different if he had been here. He would have been in the middle of it."

And in the middle of it is not always where Mondale likes to be.

It was not where he wanted to be in the presidential primaries of 1976, when he dropped out early, even though he was still showing better in the polls than a then-unranked challenger from Georgia.

And there are a number of Mondale's admirers in mid-level positions on the White House staff and in prominent positions outside it who feel that Mondale has lately chosen too often not to wade into the tough intrafamily disputes within the Carter inner circle, even when his experienced, Washingtonian counsel could have been most helpful to Carter.

"Fritiz probably goes along too often when his insides say he shouldn't" says Minnesota's attorney general, Warren Spannaus, Mondale's close friend and the cochairman of the Carter-Mondale campaign committee in the state. "He should probably be more assertive."

Spannaus adds that many Minnesota Democrats, himself included, are "very upset about the whole Cabinet shakeup." He adds, "i don't like the way it was handled at all."

And up on Capitol Hill, a senator who is one of Mondale's closest friends in Washington says he thinks Mondale probably didn't like it either. "I don't think that's the way Fritz would do it," the senator says.

Mondale came into the vice presidency with an unusual charter from the president. Mondale would be Carter's "chief staff person," Carter said, and it was explained that would mean his closest personal adviser.

In a White House populated by no one else with years of high-placed experience in Washington, that should have proved an essential ingredient for being a true White House insider, as perhaps no other vice president had been.

Mondale, in a rather unusual move for a vice president, promptly eschewed the practice that has become traditional: finding one or two things with which he could occupy his time and make his mark, the way Hubert H. Humphrey devoted himself to the space council and Nelson A. Rockefeller to a reorganization of the intelligence agencies.

Mondale did succeed, because Carter wanted it that way, in becoming a key member of the Carter inner circle - he was in on all of the big meetings, and he has lunched privately with Carter once each week. Mondale's staff has also functioned as no vice president's staff had before it, as a genuinely integrated part of the White House staff.

Mondale's top aide Richard Moe, for example, heads Carter's White House task force efforts for pushing the hospital cost containment and national health insurance bills through Congress. He presides over meetings of Carter aides and guides them through the what-to-dos.

"My feeling is that the president has been drawing closer and closer to his inner circle of Georgians," laments a senator who is Mondale's close and personal friend. "I think Fritz is still closely consulted on matters of policy. But not necessarily on personnel matters, such as which advisers should stay and which should leave."

Actually, Mondale has been assigned a modest role in administration personnel matters in recent months. It is the sort of role a corporal is assigned when somebody has to tell the buck private who broke curfew to put up the cigarette butts that litter the parade grounds. Mondale was in charge of policing Califano.

A month 05or so ago, the president got word from some members of Congress that Califano was not giving full support to the bill that would create a separate education department, a campaign promise Carter intended to keep. So he told Mondale to bawl out Califano and get him in line. And Mondale dutifully issued the rebuke to the man he had originally sponsored as head of the Health, Education and Welfare Department.

Then, when Carter was at Camp David having just canceled his scheduled July 5 energy speech, he was angered to hear that Califano was spending five days in Hawaii on his way back from a vist to China.

The education department bill and the hospital cost containment bill were both nearing crucial votes on Capitol Hill, and so an angry Carter is said to have told Mondale to call Califano and tell him to "get his a-- back here."

Mondale made the call from Camp David on Thursday night. But, he did not tell Califano to get his posterior post haste to Washington. Nor did he even tell Califano that the president was displeased with him once again.

Califano and Mondale have both confirmed this via aides. Mondale simply asked Califano when he was coming back to Washington. Califano answere that he was leaving Hawaii "tomorrow night," and Mondale figured that was good enough, so he let the matter drop and in the process let the message fall between the cracks.

So now Mondale sits hunkered down in his office of the vice president, which aides still proudly point out is just a few feet down the corridor from the Oval Office, refusing to discuss the matter of the Cabinetshakeup, or how it happened, or the global consternation that followed.

Even Carter has said to his staff that perhaps the idea of mass resignations was a mistake, considering how it was interpreted around the world. But Mondale just sits in his office, saying, please don't misunderstand, but he just simple would rather not say. Instead he issues a one-sentence explanation that to even talk to a reporter about the events of the past week would breach the confidentiality of his relationship with the president. It is strange to hear a plea of executive privilege copped by a man who used to enjoy comfortable and rather unfettered relationships with the press.

As one of his top assistants put it, "What you want to know is, what did the vice president know and when did he know it? And he just doesn't want to say."

There are two explanations available as to why he doesn't want to say; and they are not necessarily mutually exclusive.

The first was written years ago by Eisele, who is now Mondale's press secretary but who was then a Washington correspondent. In 1974, Eisele wrote, news that Mondale had his appendix removed "caused some [Minnesota] Democrats to say they hoped the surgeon inserted some guts before sewing him up."

The other was given just the other day by a member of Carter's staff who is one of Mondale's boosters on the inside. He said: "It is like the age-old question: If a tree falls in the woods and nobody is there to hear it, does it really make a sound? In this case, it is simply in Mondale's interest not to make a noise."

EPILOGUE: Because Mondale was in Kansas when the president convened his now-historic Cabinet meeting, he missed out on a rare opportunigy to take charge. At about noon, after the neeting had been going on for some time and the matter of mass resignations had already been discussed, the president announced to his Cabinet that he had some other business to attend to.

And he excused himself from the table and left the room, according to a source who was there, asking Hamilton Jordan to preside in his absence.

And in a rare, and perhaps unprecedented occurence, Jordan, who is not a member of the Cabinet, ran the meeting for the final 40 minutes or so, as the most senior officials of the government took their cues from the 34-year-old man who Carter had told them would be his chief of staff - with authority "almost equal" to that of the vice president. CAPTION: Picture 1 and 2, VICE PRESIDENT MONDALE...distancing himself from the firings modest role in personnel matters.