Compartmentalization: What President Obama accomplished on his Asia trip

"Compartmentalization" is my working view of President Obama's main accomplishment on his Asia trip. The only visible action in Japan was his statement that the US is bound by treaty to defend Japan's administration of the Senkaku/Diaoyu Islands. He still gave China one avenue to pursue, the International Court of Justice.

The effect of his statement will be to reduce the chances of a nasty surprise over the possession of these islands. A side effect is to essentially sideline Japan so that the US can pursue engagement with China with less attention to Japan's views. The US has concluded that Japan will not become a constructive partner with respect to China, so it will settle for Japan on the sidelines.