The man who invented shuttle diplomacy was openly optimistic about the current efforts of Jimmy Carter, latest disciple of Kissinger-type negotiating.

'I think," said Henry Kissinger, his face the rich color of Acapulco cordovan, "I think this phase will succeed, and there will be another phase. But that's inherent in the Middle East.

"It's risk for Carter, yes, but doing nothing is also a risk. I assume that he went with the reasonable assurance that it would work."

Kissinger, accompanied by his wife, Nancy, had not been inside the Embassy of the Federal Republic of Germany five minutes last night before he had fallen into conversation first with CIA Director Stansfield Turner about the shah of Iran, then with a former State Department lieutenant about the Israeli-Egyptian peace agreement.

If anyone wondered about the interest level of retired secretaries of State in foreign affairs, whatever the politics of moment, those doubts were soon dispelled by watching Kissinger work his way through a bipartisan crowd of several hundred invited by Ambassador and Mrs. Berndt von Staden to celebrate the 150th birthday of another famous German-born American who made good.

That was Carl Schurz who managed to outdistance even Kissinger by becoming not only a U.S. cabinet officer (secretary of interior under President Rutherford B. Hayes) but before that a general in the Union Army, then a civil rights advocate for President Andrew Johnson, then a newspaper editor, then a U.S. senator from Missouri.

"Dr. Kissinger has not yet become a United States senator but here I stop because I don't want to become involved in American politics," von Staden wryly told the audience when introducing Kissinger.

"When the ambassador so tactfully speculated on my political ambitions he resorted to understatement," said Kissinger equally wryly when his turn came to make what were euphemistically described on the printed invitation as "remarks."

In fact, Kissinger would have his listeners believe that, politically, his sights were trained on the western end of Pennsylvania Avenue rather than the eastern.

And if some in the crowd were quite serious, indeed, that it was the United States' loss that Kissinger could never become president ("If he'd been born here, he'd have been nominated by both parties," ventured former Kentucky Sen. John Sherman Cooper), Kissinger at least played the eternal optimist. A 1974 amendment introduced in the House of Representatives to give foreign-born citizens a chance at the presidency may have only achieved three votes in five years, he said, "but I'm looking forward to a long life."

But in the end it was the eternal professor who won out emerging to put last night's occasion into a serious perspective through a kind of Kissingian overview of German history if not world politics.

"I agree," said Cooper, agreeing at least about what Kissinger had called the "complexities" of nations having to share territories "imposed" from the outside by other nations.

"Nancy, you were wonderful to come," Wendy von Staden told Nancy Kissinger -- which her husband quickly translated as "Wendy means it's time to go." And they left.