Tokyo -- Now that there's no Cold War, can there still be peaceful co-existence between the two superpowers?

The question began to seem real somewhere partway into last week's summit face-off between the men who head the two economic titans of the new world order. Late Wednesday afternoon, say, maybe three or four hours before the president of the United States fell to the floor puking on the prime minister of Japan's pants-leg.

There's been a lot of punditry printed and broadcast about how the post-Cold War world will be dominated by economic rather than military power. Maybe it was inevitable that the first real summit of the new era would be drowned by trade negotiations.

Still, there was a certain strangeness.

Here were the triumphant leaders of the two surviving superpowers, representing 40 percent of the Gross Planetary Product. Two men who have prepared themselves by decades of service at many of the historic crossroads of the second half of the century.

They came together for the kind of ultra-high-level meeting that Nikita Khrushchev and John F. Kennedy invented to keep us from frying each other with megatonnage and multiple warheads.

L And the central issue was a quarrel over 19,700 automobiles.

At the working level, where summits past have dealt with the nitty-gritty of submarines that carry ICBMs and documents that carry names like Strategic Arms Reduction Treaty, the negotiators worked on how a car's turn signals ought to blink and who could display autos on showroom floors at downtown Tokyo dealerships.

Incredibly picayune as it all was, what lent the sense of strangeness was a feeling that there might be something even more incredible -- a nagging worry that maybe it mattered.

That it mattered because the larger stakes could affect the daily lives of millions of people, not only in Japan and the United States but in virtually every country in the world.

Just as the summits of the Cold War were not really about throw weights and classes of rockets but rather about whether to incinerate the world, the first summit of the post-Cold War was not really about bumper strengths and wheelbases but about whether to have a trade war.

And, just as the summiteers of the Cold War never spoke of having a nuclear holocaust but only of peace, the first summiteers of the post-Cold War never spoke of resorting to protectionism but only of free trade.

But the parallels were less than perfect.

The heavy focus on trade issues came about not out of mutual need but out of Mr. Bush's.

Twice, the Japanese had prepared for a more traditional summit. What they wanted was the recognition and the honor of at least one state visit from their most important ally.

The honor was important not only for its own sake but also as a way of helping get Japanese voters used to the idea that affluence carries with it the burden of broader responsibilities in the world.

They had long felt slighted as they watched history at the Berlin Wall, at the Kremlin and in the Middle East preoccupy their most important ally and keep him from visiting a country he kept saying was second to none in the U.S. scheme of things.

Last January, Mr. Bush canceled because of the Gulf War. Last November, he canceled because his popularity was plummeting a recession year and he didn't dare leave the country while a Democrat-controlled Congress was in session.

Then, in December, he at last scheduled dates that seemed likely to stick.

Within days, he set about covering his flank at home.

This would not be just another trip by a president enamored of foreign affairs, he vowed. He would make it a crusade in Asia to create "jobs, jobs, jobs" for American workers.

Then came his bold stroke.

To get those jobs, he would take along a phalanx of captains of American industry. Heading them: the chief executive officers of the foundering Big Three automakers.

Combined with the promise of "jobs, jobs, jobs" amid recession, it was a stroke that turned the first post-Cold War summit into a production unlike anything Kennedy or Khrushchev could have imagined.

No matter how refined the dialogue of the two summit principals, the gentlemen from Detroit were products of a rough- and-tumble corporate culture that has little use for diplomatic circumlocutions.

Where the fear of nuclear holocaust was the never-spoken background of the Cold War summits, the threat of a trade war became the constantly discussed foreground of the first post- Cold War summit.

If the Japanese didn't soon set about the job of reducing their $41-billion-a-year trade surplus with the United States, the gentlemen from Detroit averred, it might soon be time to pass a law about imports of Japanese cars to the United States.

Just as shooting wars are always declared in the name of peace, the men from the Big Three made clear that any U.S. law on Japanese car imports would of course be adopted in the name of freer trade. Its goal, after all, would be to force the Japanese market open, wouldn't it?

Trade wars, of course, don't make planets incapable of supporting life.

But economists often point to the Great Depression of the 1930s as evidence that trade wars can make workers incapable of supporting their families. And whole national economies incapable of supporting their populations.

Summit meetings tend to focus the public's attention -- and to focus attention most forcefully in the capitals where they are held.

The Tokyo summit was no exception.

From taxi drivers to magazine cartoonists, it became difficult by week's end to find anyone in town who was not either angry with the American pressure or contemptuous of a country that coped with its own problems so badly that its head of state had to go begging its chief competitor to buy more cars.

The summit riveted attention almost equally in America.

For three years of his presidency, Mr. Bush worked steadily at calming the always-choppy waters of Japan-U.S. relations.

Now, with his "jobs, jobs, jobs" crusade and the three days of immensely increased visibility the corporate executives gave his trip, Mr. Bush may have done more to demonize Japan in American minds than all the professional and semi-pro Japan-bashers running against him.

For the Japanese, the timing is ironic.

They had spent most of a year worrying that the 50th anniversary of Pearl Harbor, with its excruciating memories, would bring new waves of election-year Japan-bashing.

Partly thanks to Mr. Bush's own words at the Pearl Harbor memorial ceremony -- "enemies have become friends" -- Dec. 7 came and went with little impact.

The Tokyo summit did not.

This time, Mr. Bush, head of an administration that savors "spin control" to make sure the voters' impression of events is favorable to the president, had brought along his own spin-busters.

"Success," Mr. Bush said of his trip.

"Inadequate," the men from Detroit said.

It was not as if their views had been unknown.

Chrysler Corporation's Lee Iacocca would be on anybody's All-America list of Japan-bashers.

He went home angry. Steeped in the prestige of a presidential jobs crusade, he got what he loves most -- attention -- when he gave a much-publicized speech at a tailor-made venue, the Detroit Auto Show.

Past summits always made nuclear war seem more distant.

Nobody thinks trade war is yet at hand.

But the first post-Cold War summit made it seem less distant.

John Woodruff is The Sun's Tokyo correspondent.