TOKYO -- The conventional wisdom on the other side of the Pacific is that U.S.-Japan relations are the best they've ever been. The view is very different in Japan. Here, an increasing number of voices argue that the benefits of the relationship only flow one way. On a recent visit, I was continually challenged to explain just what Japan was getting out of these "historically good relations." The questions underlined the unease that influences and threatens to dominate Japanese security thinking.

In Washington's eyes, the U.S.-Japan relationship just keeps improving. Some credit the "George-Jun" friendship shared by the president and the prime minister; longtime alliance watchers say it has eclipsed the "Ron-Yasu" era of the 1980s, the previous high-water mark. Prime Minister Junichiro Koizumi deserves credit for seizing the opportunities that followed Sept. 11, and taking the initiative in ways that no other Japanese prime minister had. Others note the groundwork laid by alliance supporters on both sides of the Pacific who vowed ties would never again be as strained as they were in the early 1990s. No matter what the cause, the result is the best relations ever and, according to one administration official, Tokyo's "unprecedented influence" in Washington.

Yet for all the applause and optimism in the United States, there is considerable unease in Japan. This nervousness takes several forms.