US Ambassador and eternal professor Arthur Burns strolls into his living room in an open-necked, discreetly checked shirt and greets the dozen-odd students and nonstudents invited here this Sunday afternoon.
He seats himself on the sofa in front of the room's focal point, an 18th century painting of Berlin. A servant pours coffee into china cups, and Burns proposes a few topics for possible discussion in this umpteenth monthly ''seminar'' he has hosted in Berlin - but he invites anyone to talk about anything. ''There are no improper questions,'' he notes. And he likes listening to young people's ideas.
There are a few tentative comments about investment in West Berlin. Then a Green who has split from the city's countercultural Alternative List over the latter's ambiguous stance on violence approaches the hottest political issue today, the imminent stationing of new American missiles in West Germany.
''We would like to ask how you feel about the Bundestag vote to accept missiles,'' he begins.
Burns replies to the polite probe in the same folksy tone in which he conducted so many interest rate battles in his years at the Federal Reserve Bank.
''I'm pleased that the government acted that way,'' he says. ''I do not love missiles. I wish we didn't have to have any of them. . . . If the Federal Republic (West Germany) had decided not to deploy the missiles, then I think NATO would have become an empty shell. . . .'' It's an answer that would have been laughed down the night before in the group of 50 that gathered in Berlin's Memorial Church to discuss the American nuclear war film ''The Day After.''
But in this living room with this mixed group of Greens, young conservatives, and young Social Democrats such low-keyed words issuing from the mouth of this white-haired authority have an effect. The next probe from the Green is as polite as his first.
Is President Reagan - the young man avoids a direct challenge by paraphrasing a headline in the Paris Herald Tribune - ''steering for war''? And wouldn't it have been better to take US taxpayer's money for sending troops to Grenada and put it into economic aid?
''Let me say this. First, between 1968 and 1980 defense spending in the United States expressed in real terms kept on declining year by year. During that period Soviet spending on the military kept increasing sharply year by year. We practiced to an appreciable degree unilateral disarmament. The Soviets did not follow us. . . .'' He continues, ''There is a difference between the European parliamentary system and the United States. We can elect a former actor , a former peanut farmer, a former haberdasher'' as president. ''It's a learning process'' for any inexperienced president.
Some more talk about Berlin, high-tech industry, possible reunification of Germany, and the need for GIs here to mix more with Germans, and the two hours are gone.
The ambassador accompanies the young people to the door. They thank him for the conversation and one left-liberal remarks to an American diplomat how different such personal contact is from reading about the US in the newspapers. The ambassador, she feels, is ''honest.''
A lot more of America has been communicated in this afternoon, it seems, than just policy.