A new study by the Council on Foreign Relations has found that current economic strains between the United States and Japan could undermine the close security relations between the two nations and push Japan back into "insularity and defensive nationalism" if they are not properly managed.

The study, by Ellen L. Frost, said "the underlying source of these tensions ... is the rapid shift in the relative wealth of Japan and the United States. In relation to each other, Japan has gotten richer and the United States has gotten poorer.

"Adjusting to this transition alone would strain any alliance, let alone a partnership that seeks to transcend differences in race,language and culture, memories of World War II and the world's largest body of cold water."

But Frost, a former government official who now works in the Washington office of Westinghouse Electric Corp., said the economies of the United States and Japan are already "so closely intertwined that forced separation would be wrenching and probably impossible.

"They are in it for good, so to speak, thrown together for richer and for poorer," she said.

"For the rest of this century and beyond, divorce between the United States is economically impossible, militarily impractical and politically unthinkable," Front wrote.

The study is contained in a book, "For Richer, For Poorer: The New U.S.-Japan Relationship," that was released yesterday.

Frost decried the current U.S. trend toward "Japan bashing" that is especially prevalent in comments coming from Congress. She said this is producing a reaction in Japan that sees "an America wallowing in self-induced industrial stagnation and extravagant spending habits" and could lead to a resurgence of "racial-national arrogance and hostility to Western values."

"An ominous combination of attitudes has appeared," Frost wrote. "America's lingering complacency, residual 'number-one' mentality and new sense of vulnerability are the mirror image of Japan's lingering sense of vulnerability and new arrogance," Frost wrote.

Instead, she recommended that the United States adopt a policy of "constructive pressure" on Japan, avoiding emotional attacks that can be counterproductive.

She suggested a "coalition strategy" that builds on shared values and pushes for change on the basis of Japan's self interest, not America's.