Why do I live in this jungle called New York, this outdoor oven where rolling furnaces of taxis ply potholed and dangerous summer streets? This was the question that Alistair Cooke posed to himself on a recent Saturday after returning from a restful vacation trip to London. His answer to his own question is worth reflection in these final, unrestful days of August.

For many Americans, the silver-haired, silver-toned Cooke is a living symbol of British culture. His elegant introductions to British serials on public television have earned him a devoted following here in his adopted land. But abroad, it is as an astute observer and interpreter of America that Cooke is revered.

For more than 40 years he has narrated a 15-minute weekly ''Letter From America'' on BBC radio, shortwaving the foibles, virtues and folkways of Americans to the rest of the world. It is the only radio broadcast that I have relentlessly monitored since "The Comic Weekly Man" enlivened the Sunday mornings of my childhood. He too was an artist who understood Cooke's dictum that radio ''is literature for, so to speak, the blind.''

Take the July broadcast in which Cooke voiced his brief moment of doubt about his choice to settle in New York half-a-century ago and to stick it out. In this "Letter," Cooke used H. L. Mencken, Winston Churchill, Hermann Goering, Ogden Nash, James A. Baker III and John F. Kennedy as verbal footnotes -- all to the point he was making, concisely, without ostentation.

The starting point for this journey across cultures was a by-the-way remark that during his visit to London he had saved two Americans from Austin, Tex., from being run down in London traffic as they stepped off the curb. They were doing what American visitors to London always do -- looking the wrong way when crossing the street.

The incident recalled to Cooke Mencken's warning that in London ''any man who steps off the sidewalk takes his life in his own hands.'' This led to the fact that Churchill in a life of adventure and danger suffered only one really serious injury -- when he was hit by an automobile in New York as he looked right instead of left as he stepped from the curb.

From Churchill's accident as a result of differing American and British street habits, it was a quick hop for Cooke to an explanation to me (and perhaps to other listeners) why I am always uncomfortable walking London's sidewalks as well as dodging across its roadways.

He noted that we Americans walk as we drive -- on the right, directing ''two rough streams of human traffic'' on the sidewalks of our cities. But in London, Cooke observed anew that there is no custom of the sidewalk, no established pedestrian lane. You duck and weave through a milling mass, even in Belgravia, the splendid district that Goering saved from Luftwaffe destruction because it would make a majestic site for the British capital of the Third Reich.

I heard this particular broadcast in Paris as I packed at the end of a four-year sojourn and prepared to move back to Washington, in open defiance of the prevailing view that the conduct of world affairs is slipping through the fingers of Americans to be taken over by the Europeans and the Japanese. Cooke's uncharacteristic doubting question about living in America today chimed that same pessimistic key in my ears for a moment.

But like skilled lawyers, skilled commentators only ask questions to which they already know the answers. That morning Cooke had noted that American newspapers devoted front-page articles to a shift in U.S. policy on Vietnam and Cambodia. Here was a distant, difficult subject ''on which the United States was not expected to be a spectator.'' Cooke saw fresh proof that ''the burden the United States has carried since World War II'' in the Pacific and elsewhere could not be put down so easily or rapidly.

To live in America is to look at events ''from a different curve of the planet,'' in Cooke's succinct response to his own question. The more comfortable and settled societies of Western Europe and Japan may have global pretensions, but they do not have global perspectives or capabilities. For better or worse, the burden of global responsibility still lies with America.

Cooke spoke of America's continuing ''burden'' at a time when Saddam Hussein's ambitions and cruelties were of concern only to a few Americans -- George Bush and Jim Baker not among them. But Cooke captured the underlying reality of Bush's response to Saddam's banditry before it happened.

This kind of insight makes Alistair Cooke the de Toqueville of the shortwave band, the premier interpreter of America in our time. It is our good fortune that he has known all along why he is in America.