They went to dinner at the White House and were welcomed with all the pomp and dignity a presidency can offer.

Teng Hsiao-ping, purged and rehabilitated.

Richard M. Nixon, pardoned and, at least last night, resurrected.

For Teng, who had never been there, it meant a new era for his people, one last coming-out celebration of the new China diplomacy.

For Nixon, who once lived there, it meant a return to the old era -- a time when he would wear black tie and bathe in the respectability of the White House.

More important, it meant a time when he would be remembered for his foreign policy and not Watergate; when he was looked upon as a statesman and not an unindicted co-conspirator.

The decision to invite Nixon back to the White House he left in 1974, in tears and disgrace, was made in tears and disgrace, was made rather quickly by President Carter.

It happened weeks ago, at one of the regular Friday White House breakfast meetings of the president and his chief foreign policy advisers.

Hamilton Jordan brought up the matter.

Should Nixon, Gerald Ford and Henry A. Kissinger be invited to the state dinner honoring Teng?

"The political benefit was obvious," recalled one adviser who was there. "It was discussed briefly."

The political benefit would be that inviting Nixon and the others would be a dramatic way of countering the conservatives, who surely would attack Carter for having abandoned Taiwan by ending the mutual defense pact with that island government as a precondition for normalizing relations with Peking.

It also would emphasize that it was Nixon who had blazed the China trail and who would have completed the normalization process in his second term, had Watergate not interceded.

Also, the Chinese had said that Teng, at some point during his swing across the United States, wanted to see Nixon.

"The president's response was immediated and conclusive," the aide said. "He said Nixon had begun the process and so he should be invited."

Zbigniew Brzezinski's staff expert in China, Michel Oksenberg, was quietly dispatched to San Clemente, Calif., where he briefed Nixon.

Nixon's return had been set in motion. So had the controversy that went with it.

Washington is a city that keeps in touch through dinner parties. At one a few nights ago, several leading figures in the Watergate special prosecutor's office fell into conversation about the man they had left unindicted.

They found themselves in basic agreement:

Now, for the first time, Richard Nixon is reaping a benefit that he would not have had if special prosecutor Leon Jaworski had followed the recommendations of some of his assistants and indicted him for his role in the Watergate cover-up.

Later, in an interview, Richard Ben-Veniste, who was assistant Watergate special prosecutor, explained his view:

"If Nixon had been indicted and then pardoned, or indicted and convicted and then pardoned, I think it would have made a difference... I don't think he would have been invited to the White House...

"My own opinion is that this does not do a great service to the American people. Nixon's betrayal of public confidence and trust should not be legitimized in this way."

In Houston, Jaworski looks at it somewhat differently. Jaworski, who returned to private law practice, thinks his decision not to go for Nixon's indictment was proper -- and he doesn't think it would have mattered on way or another whether Nixon was indicted.

"If there had been an indictment, it's reasonable to assume that he would have been pardoned before he had come to trial," Jaworski said. "... And I doubt that it would have made any difference" in whether Nixon was invited back to the White House. "His acceptance of the pardon implies guilt. You don't accept a pardon if you don't needs it."

Jaworski said somebody recently sent him an editorial from a North Carolina newspaper. "It said that it was okay to invite Nixon to dinner," he said, "but that they should have had me sitting there on one side of him and Judge [John] Sirica sitting on the other. Can you imagine how that would have been?"

Not all of those who opposed the return of Nixon to the White House did so because they think he deserves worse. There are those who think he deserves better.

"I wish to hell he hadn't come," said one man late yesterday afternoon.

The man is, now, a business executive building his career. In 1969-1974, he was one of those who made his way through the "Berlin Wall" and into the inner circle of the Nixon White House -- clean-cut, well-groomed and very much a believer, even when Watergate messed up his life as it did the lives of famous men around him.

"I think Richard Nixon is being used by Jimmy Carter," he said. "Clearly he's being used. His appearance at the White House is Carter's way of saying, 'If you don't like our China policy, don't blame it on me -- Nixon started it.'

"I mean, think of it in business terms: Inviting Nixon is an investment on Jimmy Carter's part. He's willing to give Richard Nixon a certain respectability. And his return on that investment is that Richard Nixon is seen as approving -- at least tactily -- of the administration's China policy."

How does he figure Nixon feels about this?

"I'm not sure. But I think he must be ambivalent. He must find it awkward, demeaning. He must be aware of the manner in which he is being received. But it plays on the emotions of Richard Nixon, I'm sure, because at least he is back with some honor had dignity."

CBS commissioned a poll to find out how most Americans felt about the invitation to Nixon.

The results indicated Carter probably has done himself no political harm, and may have done himself some political good.

About 52 percent approved of the invitation, 42 percent disapproved and 6 percent had no opinion.

So the survey results were not bad, as the Carter people saw them, and not bad as the Nixon people saw them. But the fact that someone would even commission a poll about an invitation to a dinner was indication enough that the matter was sensitive.

And so, last night there was a certain uneasiness -- an awkwardness, in fact -- that could be felt in even so gala an evening as the historic visit of a Chinese leader in the White House.

It was an uneasiness felt, expecially, by a number of the liberal members of the Carter staff. They spoke of it only when asked, but they were uneasy when they talked. "It really doesn't bother me all that much that Nixon's here," one said. "Well, I'm not all that outraged," said another. "I mean, after all, Teng did say he wanted to see Nixon sometime during his visit."

And it was an uneasiness felt, apparently, by Nixon.

He had come to a stop, momentarily, atop the stairs of the North Portico -- he had not been there since he resigned in 1974 to avoid impeachment. And just before he entered, a reporter asked him how it felt to be returning.

His response, spoken softly, had little to do with the question.

"I'm here as a guest of President and Mrs. Carter. I look forward to seeing them again. I don't want to comment on anything else," he said.

The Carters, for their part, tried to ease the situation as best they could. At their invitation, Nixon was escorted upstairs to a special small reception with Teng, which was held while most of the invited dignitaries remained downstairs.

Nixon walked through the upstairs corridor that was once his home, past rooms in which he had lived. He talked briefly with his hosts and the guest of honor in the Yellow Sitting Room that had been the scene of an emotional family discussion when he was deciding to resign.

Downstairs, the larger reception rolled on in the East Room, where Nixon delivered his weeping, wrenching farewell to his staff on Aug. 9, 1974, the one where he admitted "mistakes" but never guilt, and where he said of the mansion: "This house has a great heart, and that heart comes from those who serve."

EPILOGUE: Well into dinner, with the awkwardness of just being there somewhat behind him, Nixon, prodded by Brzezinski, entered into the small talk of his table.

Carter's national security affairs adviser had asked Nixon to name some of the world leaders he admired. "You won't catch me naming them," Nixon replied, according to one guest at his table. But then he listed a few. "Charles de Gaulle... the shah of Iran..." and, with China's Vice Premier Fang I among those listening, Nixon added: "Chiang Kai-shek."