"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones." - Albert Einstein
America will never back a nation against China because China is too vitale to America's eco. Japan DOESNT even have a strong military. THEY CANT! HA Japan's military is restricted by Article 9 of the Constitution of Japan of 1946, which states that "Aspiring sincerely to an international peace based on justice and order, the Japanese people forever renounce war as a sovereign right of the nation and the threat or use of force as means of settling international disputes." Thus, Japan's current constitution prohibits the use of military force to wage war against other countries. Japan may have one of the most technological advanced militaries but they dont have enough numbers of men to fight and they cant cause war or show any imperalistic goals by military ways.
If Taiwan became a part of Japan, Japan would probably lose its economically super-power look. That's because Taiwan is pretty poor compared to super-devloped countries like Japan.
that is why the U.S military had to take on the responsibility of protecting Japan (the whole bombing Japan thing). They were/are restricted from "most" military actions and would have been left defenseless if it wasn't for the U.S. having to be there to protect the country. We currently have more than 3 in military bases in Japan. As far as China being too great an asset...let me think, not. All China does (no offense) is make china (plates, glasses etc.), toys, clothes and some other crap that can be easily made, but we (for the most part) don't feel like doing it. China doesn't truly have anything of great value that we wouldn't be able to do without or wouldn't be able to get from somewhere else. Am i saying that a conflict would happen...most likely not Do i want a conflict, no (still doing the whole iraq b.s.) Does this hypothetical really matter, not really...if it happens, then it happens. Do i really care about Taiwan being annexed by anyone, not really