Helmut Kohl has been to the White House so many times in the past 12 years, joked President Clinton at a state dinner for the German chancellor last night, that “on his last trip here he took me to his favorite restaurant. I’m happy to announce that after the dinner, Chancellor Kohl will be conducting tours of the White House.”

The crowd of 128 politicians, diplomats, businessmen and others in the State Dining Room chuckled politely, but that was about as lighthearted as things got in what turned out to be a somewhat restrained and low-key reunion of the two leaders.

Kohl arrived Wednesday night in a lightning-quick visit to Washington to take the new Republican pulse on the Hill, and while he was at it, reconnect briefly with his old buddy, “Mr. President, Dear Bill.” Immediately

after the dinner he departed for Germany, according to White House aides, taking a chopper from the Ellipse to his waiting jet at Andrews Air Force Base. He didn’t bring his wife because she had the flu.

Clinton’s restaurant joke referred to Kohl’s visit here a year ago when the two repaired to Filomena’s, a posh Georgetown restaurant, where they gorged on impressive quantities of ravioli and zabaglione.

Last night, Kohl was still a portly fellow, to put it mildly, whose Sydney Greenstreetish proportions seemed in danger of dwarfing the not-exactly-diminutive Clinton. Remarked one observer, “He looks like he swallowed Kissinger.”

In his return toast, Kohl thanked Clinton for his “warmth” and for the friendship and support that America has shown an often troubled Germany, including the post-World War II food aid that Kohl said he remembered waiting for in a schoolyard in his home town of Ludwigshafen, which the Clintons visited last summer.

But Kohl didn’t let the guests forget that he had some pretty spiffy Republican connections as well, which was a smart idea seeing as Sens. Jesse Helms (R-N.C.), chairman of the Foreign Relations Committee, and Strom Thurmond (R-S.C.), president pro tem of the Senate, were among the guests.

“I remember when Ronald Reagan went with me to the Brandenburg Gate,” Kohl said diplomatically. He remembered Reagan dramatically demanding, “Open that gate,” as if he were speaking to Soviet leader Mikhail Gorbachev himself. Later, Kohl told the guests, he stood at the Berlin Wall with President Bush at a time when there was “a feeling of change” in the air.

And finally, “Bill Clinton and Hillary Clinton and my wife and I were fortunate enough to walk through that gate,” Kohl declared, adding that this was “because you stood shoulder to shoulder with us.”

Kohl, who barely squeaked into office himself for a fourth and final term last fall, is at least a historian who covers all his bases.

As a politician, he is hanging on by his fingernails at home -- his Christian Democratic Union and its allies, the Christian Social Union and the Free Democrats, received barely 48 percent of the vote -- and last night he stuck largely to personal themes and appeared grateful for the warm if somewhat subdued reception from the Clintons and some newly powerful Republicans.

Both Thurmond and Helms were among a select group from the Hill ushered quietly into the Blue Room after dinner for a special little tete-a-tete with Bill and Helmut.

While this was happening, Hillary Rodham Clinton convened a small news conference in the hallway and said that at dinner she and Kohl, who sat next to her, talked about how Kohl surprised everyone by winning reelection.

“He {Kohl} actually is a veteran politician, and he has an enormous respect for the president,” she said. “I think he believes the president’s done a good job for the country, and so I think it’s natural for him to expect the election to turn out, you know, the way his {Kohl’s} did.”

Helms, who had met with Kohl on the Hill earlier in the day, said as he entered the White House that the meeting had been “great. Great. He’s a good guy.” Asked what Kohl wanted from America, Helms said, “He didn’t state to me he wanted any thing. Maybe he understood that I wasn’t the one to ask.”

Indeed, it’s a little hard to know in Washington right now who is the one to ask, and House Speaker Newt Gingrich (R-Ga.), with whom Kohl also conferred yesterday afternoon, was elsewhere last night.

Henry Kissinger was there, though, drifting in through the guest entrance like some grand ghost of crises past. However, when quizzed by a reporter about the great uncertainties lurking at the heart of Europe today -- and Kohl’s concern over Russia, Bosnia, NATO and European security in general -- Kissinger replied in measured tones, “I think I’ll not make any great pronouncements.”

Hillary Rodham Clinton wore a striking low-cut Oscar de la Renta burgundy gown, with cashmere on top and a flared taffeta skirt. Her hair was swept back in an elaborate bun.

In the receiving line, the president was making jolly with everyone whenever he could. “It’s been so long!” he said jokingly to Vice President Gore and his wife, Tipper, who were the first in line.

And when Thurmond came through the line with daughter Juliana, Clinton boomed out cheerfully, “You’ve outdone yourself. We were talking about you. . . . It was all good.”

Actress Ruth Warrick -- a fellow traveler on Clinton’s 1992 campaign bus, and far and away the grandest dame of the evening in ruby satin trimmed with matching ruby fox -- was also the most loquacious. She predicted that not only would Clinton be reelected but also that the Democrats would reclaim Congress in 1996.

The guest list was somewhat low-key and sober, just as the evening, with little of the movie star and other celebrity glitter that these events often have. Singer Tony Bennett, who entertained after dinner in the East Room, was one exception. The quite tanned Bennett arrived with Susan Crow, who was wearing a bare-backed gown and appeared to be approximately a quarter his age. After Bennett sang, Clinton called him “young and alive,” and noted that he had heard the crooner when he was in high school in Arkansas.

When it came time to eat, Clinton and Kohl had more on their minds than European security, and absolutely no interest at all in lean cuisine. The leaders, dominating two of the 13 tables gleaming with the Reagan china, red floribunda and vegetated pittosporum in vermeil containers, chowed down on a menu that was a tour de force of caloric content. White House chef Walter Scheib, an expert at such things, knew better than to count the calories.

“I’m sure that’s classified,” he demurred to reporters earlier.

Classified or not, for the next hour and a half, the chancellor, his host and 126 other diners, including Mrs. Clinton, devoured herb-roasted Pennsylvania pheasant breast with wild mushroom risotto and tomato basil coulis, pan-seared salmon loin with key lime and ginger, Oriental vegetable confetti and rice noodle crisps and marinated New York state goat’s cheese and vegetable terrine with young greens, topped off by a coffee and roasted hazelnut ice mold with cinnamon sabayon and light chocolate sauce and macaroons plucked from chocolate baskets created by pastry chef Roland Mesnier. Of the three wines, two were Californian and one was from Oregon.