Just two seats away from the president, in the Roosevelt Room, the labor union official strained forward to hear.

Jimmy Carter was trying to lead his stalwarts into action, in this rally-the-loyalists session early in his presidency.The room was virtually silent - and that was the problem. The sotto voce message of the commander-in-chief was being drowned out even by the clinking of ice cubes in water glasses, the rusting of paper.

"I was never so disillusioned in my life," recalled the labor official, a pro-Carter man who had matched his convictions with large amounts of campaign cash in 1976.

"Here was the president - my leader - trying to urge us to do great things for him. And he was speaking so softly we couldn't even hear him, let alone follow him. He didn't even seem to have faith in what he was saying - so how could we?"

These old complaints of disillusionment - echoed so often in the last 2 1/2 years - came to mind Saturday because of their stark contrast to the forceful yet relaxed president whose voice filled the State Dining Room as he talked to reporters (sans microphone) about the Cabinet changes he had wrought.

It was not even the new-for-television Carter, who made his appearance on the nation's screens a week ago yesterday, his voice up a quarter octave in an effort that came off good but strident. It was a man as relaxed as he was in those days in the Pond House in Plains, back when the Cabinet prospects had come a-courtin", one by one - yet far more forceful.

There seemed on Saturday to be a new confidence in the manner of the president. And this might be the one truly new thing that has come out of all of his domestic summitry and shakeup.

The president would have the nation believe that he has just weathered a crisis and has given his administration a new foundation (although he is no longer using this phrase that was to be his hallmark). Actually, his new foundation is nothing more than a face-lifting.

And although the president and his people are making much ado about how there was this problem of loyalty, they are not mentioning that there was also a problem of inspiring loyalty.

Yet, in the end, the greatest change in this past week of tumult may well have little to do with new policies or new directions or new efficiencies or new loyalties. It may instead be that there has been a genuine change in the demeanor of the man whose job it is to inspire loyalty from the people who serve at his pleasure.

Take (since the president has chosen to make so much of it) the case of Health, Education and Welfare Secretary Joseph Califano, and the way Carter elected to deal with it in the many months past.

Long ago the president received reports from his staff that Califano was being disloyal in not showing proper deference to the White House in making job appointments. Carter told Hamilton Jordan to handle it.

Long ago the president received reports from his staff that Califano was being disloyal in holding out for a more ambitious national health plan. Carter told domestic policy adviser Stuart Eizenstat to handle it.

The president received reports that Califano was being disloyal in not fully backing the new education department bill. Carter told Vice President Mondale to handle it. And when he heard Califano was in Hawaii when he was needed on the job in Washington early this month, he had Mondale handle that too.

Since the president is now making it perfectly clear that he felt so strongly about these alleged acts of disloyalty, it is fair to ask why he did not summon the secretary of health, education, and welfare to the Oval Office during these past months and tell him, perhaps in the nomenclature of his days in the Rickover Navey, to either shape up or ship out.

It is also fair to reply that, for 2 1/2 years, that has not been Carter's style. Carter himself is known to concede now that he too often yielded to what he calls the vicissitudes of Cabinet members. Which is a way of saying that perhaps he did not get total loyalty because he neither demanded nor inspired it.

Meanwhile, as Carter gets down to the business of governing once again, the introspection he wrought in the Camp David woodland has spread, like ivy, through his senior staff.

Newly crowned chief of staff Hamilton Jordon vowed yesterday on "Meet the Press" (NBC, WRC) that he will strive to improve his reputation with some of the leaders of Congress. For most of 2 1/2 years, he stayed away from Capitol Hill, considering that to be congressional liaison chief Frank Moore's territory. He even bucked calls from senators and House members to Moore's office.

The result: while Moore continued to be a target of congressional criticism, Jordan developed a reputation as what he has called a dark figure lurking in the White House. So Jordan wants to set things straight.

Now the Carter White House is apparently going to have a chief of staff who, because he is essentially a political creature, will be spending more time on Capitol Hill and less time administering the staff that he chiefs.

Jordan has said that administrative talent is not his long suit. And the president is known to be prepared to appoint an official to handle much of the administrative duties that otherwise might have fallen to Jordan, but who will serve under Jordan. Leslie C. Francis, a congressional liaison aide from California (he will not be vulnerable to the Georgia Mafia tag), has been mentioned. Some within the inner circle have urged Carter to name a more senior and experienced Washington figure.

Carter has promised to broaden the base of advice that he gets from his White House staff. The Georgians who comprise the inner circle are all said to be safe, but additions of outsiders have been suggested to Carter, and he is about to act on some of them.

One of those most prominently mentioned to Carter at Camp David was retired Time Inc. editor-in-chief Hedley W. Donovan, a strong Carter admirer in the past. Several Washington establishment figures suggested to Carter that someone such as Donovan perhaps could broaden the staff's advice on how to get their message across to the public. (Gerald Rafshoon, Carter's director of communications, is known to have long been planning to leave the staff, to do his making of the Carter image from the outside for the president's reelection campaign.)

So there will be all these changes. For some the shakeup was musical chairs and for others it was odd man out. Hamilton Jordan has been given his head and a new hat to match, and the White House staff may have a few faces more.

But more of those will change things very much for that labor union official who sat in the Roosevelt Room of the White House a couple of years ago and came away disillusioned because he could not hear the leader he wanted to follow. For him, policies will not change very much and the Carter administration will operate just about the way it has all along.

What would have made a difference for that labor man would have been to sit at a far corner of the State Dining it be known that he had what he refers to as an overdose of confidence.

The difference would have been that the man from labor could have heard the president. CAPTION: Picture, HAMILTON JORDAN...hopes to improve Hill ties