China is not Russia either. China is a huge trading partner for the US and a source of growth for the global economy. A war with China will wreck hell on the world´s economy.
Eh? The bases can be put on hold.
It´s cute that you think that the US will jeopardize its own economic health and wealth because of Japan. Let me remind you that China is the largest holder of US debt.
http://www.ibtimes.com/top-10-foreign-holders-us-debt-china-japan-still-lead-1511752
China is a huge trading partner for the US. And let me remind you that a lot of US industry juggernauts have factories in China/contracts to manufacture goods with Chinese partners.
The US will not jeopardize all of these economic interests for Japan. The US has too much to lose if the US goes to war with China.