When Japanese negotiators returned home empty-handed after trying to work a deal with the United States on joint production of a new fighter plane called the FSX, there was surprise and anger in Tokyo.

But if Japan had been aware of growing concerns in America, there would have been less surprise. While Americans may continue to buy Japanese cars and electronics, they also are becoming more resentful of the huge trade imbalance between the two countries.This resentment is fueled by the knowledge that the Japanese government makes it difficult to sell many U.S.-made products in Japan, while expecting America to have an open door to all Japanese-made goods.

The FSX proposal came about, for example, because Japan has steadfastly refused to purchase the existing F-16 fighter, which Tokyo could easily afford and which would meet Japan's defense needs.

Instead, Japan wants Washington to co-develop a new fighter based on the design of the American F-16. Japan would fund the project, the countries would share technology, and U.S. firms would get at least a third of the development work.

Congress and some members of the administration fear that the FSX project might amount to a technological giveaway.

They believe any technology transfer would be one-sided, that U.S. know-how would be used to help Japan build a domestic airline industry to compete with U.S. firms, and that the American share of the FSX project may turn out smaller than expected due to Japanese "interpretation" of the pact.

This kind of "interpretation" happened in a deal that was supposed to guarantee America a specific share of Japan's computer chip market.

These are legitimate concerns that must be addressed.

Japan must recognize that a policy change is taking place in Washington. President Bush is not Ronald Reagan and the Reagan practice of keeping defense and trade issues separate no longer applies.

That change makes good sense. If the United States is going to help Japan build a military defense, it can hardly let Tokyo undermine the U.S. economy at the same time.

The FSX fighter plane project should remain on hold until Japan comes up with a better offer and more reliable guarantees.