Japan's alliance with the United States remains the centerpiece of its strategic policy, yet Washington appears increasingly reluctant to get drawn into Sino-Japanese territorial disputes. If anything, the U.S. seems concerned that Prime Minister Shinzo Abe may view U.S. treaty guarantees as a shield for Japan to confront an increasingly assertive China in the East China Sea.
The hard fact is that Washington seems as concerned about a muscular China as it is about a revisionist Japan.
The U.S. has a major stake in maintaining mutually beneficial relationships with both Japan and China. Although Japan remains under the U.S. security umbrella, China — as a permanent U.N. Security Council member, an emerging great power, and the biggest buyer of U.S. Treasuries — matters more to U.S. interest now than possibly any other Asian county.