I'm kind of hoping that the Japanese shoot down that NORK missile. US saber-rattling in the area will come to no avail because of Chinese counter-measures. Japan, on the other hand, can take the moral high ground. Not to mention this is no time for the US to re-open wounds inflicted by Bush by throwing its weight around.
I share some concerns about resurgent Japanese militarism a generation or two from now, but it's time for countries other than the US to pony up some capital for their own defense. The militaries of Western Europe are a joke. Not the individual soldiers or units, but their ability to project power (sometimes even within their own territory) - they are wholly dependent on US logistics, as the Tsunami relief effort clearly showed. Japan maintains a maritime security force that can project power beyond its borders, and is much closer to potential hotspots than what is left of the European navies (excluding the UK).
I'm not terribly enamored of the way the Japanese handle their own Imperialist history - the Germans were required to re-apply for admission to the human race after WWII, whereas the Japanese were not, given Stalin's quick occupation of Sakhalin. A divided Japan would have not have served Western interests at all. But the interment of war criminals in Yasukuni Shrine still galls.
I have a personal interest in the enmity between the Chinese and the Japanese - I've lived in Japan and speak Japanese (as does my wife), but my father-in-law is a former KMT soldier who fought them on the ground in Northern China.
I think my father-in-law's attitude is quite instructive. Before the War, his family did business with the Japanese, in fact he had a Japanese godmother. He still speaks Japanese to me when my Mandarin fails. However, he spits every time he sees the Imperial flag (the one with the sun's rays). I think the time to put the emotions of WWII away and ask Japan to take a more active role in the defense of the PAC rim has come.
Nothing will stop the regime in Pyongyang faster than public demonstrations of impotence, and a Japanese intercept would do that quite nicely.