If the US does not acknowledge Japan's claim then why do they officially reaffirmed that Senkaku is included within the Japan-US mutual defense treaty?
The US is walking a tightrope between assuring Japan and not provoke China too much. Japan is the keystone in the US Asian alliance, and without it, American primacy (in Asia) unravels at the seams. That's why US officials will
say anything they absolutely must to keep Japan satiated. But talk is cheap, and Abe doesn't quite trust US assurances, ergo the re-militarization and anti-China confederation.
Japan's claim towards Senkaku was included within the San Francisco peace treaty so at least all 40 signatory nation acknowledges it.
I propose we have a reasonable debate. I ask that because I think you know pretty well the 1951 San Francisco Peace Treaty doesn't mention Diaoyu/Senkaku by name. Just in case you forgot, enclosed is a link to the actual wording of the treaty.
The unfortunate fact Diaoyu/Senkaku wasn't specifically mentioned has contributed to the territorial dispute between ROC, PRC, and JPN, and caused the US lots of anxiety and headaches.
As I have posted before Japan already administer the islands and does not recognize any dispute...
Do you claim there was never a dispute over Diaoyu/Senkaku, or there's isn't one now? If the former, then explain why past Japanese administrations say there's a dispute over Diaoyu/Senkaku? Would you be reasonable and admit "no dispute" is a different policy under Prime Minister Abe, and former Japanese officials, including Prime Minister Yoshihiko Yoda, disagree with his position?
...so Japan cannot become a plaintiff at court. Who is Japan going to sue?
Again I ask you, why should China go to the International Court when the Treaty of Peace and Friendship between China and Japan worked so well from 1978 to 2010? The better short-term solution is to go back to status quo before the 2010 incidents, and once tempers cool, the three sides (ROC, PRC, JPN) could proceed accordingly.