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.