Is the U.S. Obligated to Defend Japan’s Senkaku Islands Against China? Probably
As things continue to get ugly between China and Japan over the Senkaku/Diaoyu Islands, the U.S. has tried to stay out of the way. Still, although the U.S. has tried to stay neutral on the territorial dispute, it appears the U.S. is obligated by treaty to defend any incursion by China into the Senkaku/Diaoyu. From Article V of the U.S.-Japan Treaty of Mutual Cooperation and Security:
Each Party recognizes that an armed attack against either Party in the territories under the administration of Japan would be dangerous to its own peace and safety and declares that it would act to meet the common danger in accordance with its constitutional provisions and processes.
The Senkaku/Diaoyu Islands are plainly under the administration of Japan, even if Japan does not have sovereignty over the islands. I don’t know exactly why this “administration of Japan” language is used, nor why it is one-sided (Japan has no obligation to assist the U.S. if U.S. territory is attacked). In the U.S. -Philippines Defense treaty, the area covered by the treaty is “the metropolitan territory of either of the Parties.” The Korea Treaty does have similar language “administrative control” language, although I am assuming it does so in order to exclude North Korea.
So the U.S. is basically on the hook for a defense of the Senkaku/Diaoyu. And what’s worse, Japan doesn’t have to help the U.S. at all in defending its own territory. Looks like the Japanese got themselves a nice little deal here.