Those of us who specialize in economics reporting have concluded that the only way to get an economic summit to concentrate on economic, rather than political, issues is for the presidents and prime ministers to call a summit on strategic affairs.

Then, in the perverse way in which this unpredictable world of ours operates, there is sure to be an economic crisis -- say, a stock market crash of 1929 proportions -- that will force the leaders to put aside geopolitical happenings to deal with economic problems.

At this 12th economic summit, which President Reagan labeled the smoothest and most productive of the six he has attended, the disaster at the Chernobyl nuclear reactor dominated the news. The second most-discussed topic was how to combat state-sponsored terrorism.

Economic issues clearly took a back seat, in part because the television networks aren't equipped to deal with financial or business issues that go beyond simple concepts, such as the monthly unemployment number or the latest Dow Jones stock market results. And to tell the truth, even most newspaper editors find their eyes glaze over when confronted with more complicated financial topics.

So the economic summits -- with the connivance of the principals -- have become prime-time "show biz" for TV: high officials who only will talk off the record to the print media willingly and regularly show up for the Good Morning America or Face the Nation.

Nonetheless, I believe that, when history looks back at the Tokyo summit, the summit will be remembered less for the time it gave to Chernobyl and terrorism than for a complex and dramatic scheme put forward by Treasury Secretary James A. Baker III to manage the world's monetary system.

"The United States is finally exerting its leadership in world economic affairs," said an enthusiastic Canadian official. "The amazing thing is that this leadership comes from the same Reagan administration that walked away from a leadership role less than 18 months ago."

Canada, like Italy, of course has a special reason to be grateful to Baker. His plan, which represents an effort to create much more stability in the exchange-rate markets than has existed for the past 14 years, now includes their countries in the decision-making process.

Except for the West Germans, all of the other countries express their open admiration for Baker's skill in transforming the Reagan administration from a do-little philosophy to one of active interventionism -- all the while preserving the free-market rhetoric that the public identifies with the Ronald Reagan persona.

After 18 months as Treasury secretary, Baker has three major economic initiatives to his credit. The first was the now-famous Plaza Hotel agreement in September, the basic building-block of the scheme unveiled in Tokyo.

At the Plaza, to help deflate congressional instincts to bash Japan for its huge trade surplus, Baker -- assisted by Deputy Secretary Richard Darman and Assistant Secretary David Mulford -- engineered a coordinated intervention by the so-called Group of 5 nations to bring the dollar down.

The five, the United States, Japan, West Germany, France and Britain, also agreed to coordinate their economic policies. That part of the Plaza agreement has not been so well fulfilled.

But the idea of the massive intervention they undertook ran counter to the earlier-expressed Reagan ideology. Later, in London, the G-5 agreed that the time was ripe for a joint reduction in interest rates.

After some resistance from Federal Reserve Board Chairman Paul A. Volcker and German Bundesbank President Karl Otto Poehl, the United States, Germany and Japan were persuaded to go along.

The second major Baker initiative came at the October joint annual meeting of the World Bank and International Monetary Fund in Seoul, when he abandoned the administration's former reliance on austerity as the way to solve the Third World debt crisis, and moved instead to economic growth as the solution.

The jury is still out on the Baker debt plan, but at least it was a start and remains the only debt initiative on which world leaders agree.

Now we have the economic bombshell Baker dropped in Tokyo. If successful, it could be the main mechanism guiding the economic relationships among the major nations for the next several years. In brief, it would abolish the full freedom of the markets to establish exchange rates, imposing instead a "managed float" -- a halfway house to fixed rates.

There are many who are convinced that it can't be done, that the huge flows of capital among nations will overwhelm the Baker scheme to limit the extent to which exchange rates can vary.

Many businessmen hope this third Baker miracle can be brought off, because it would enable them to make plans with greater certainty.

There are many questions about Baker third initiative, and it remains to be seen how it works out. But the fact that it was put forward and accepted by the summit was the main news out of Tokyo -- whatever you heard on the 7 o'clock news.