Why China's Adventurism in the East Sea has to be stopped now

It's the fault of the U.S. for not maintaining a strong presence in the East Sea after the collapse of South Vietnam which led to the increasing bellicose attitude of Red China. America's being bogged down in Iraq, Afghanistan, and maybe in Pakistan as well, in addition to its suffering from the economic crisis don't help either. America has to show Red China that its adventurism and absurd cow tongue doctrine are not acceptable otherwise China will keep on flexing its muscles to a point of no return as Japan did in the 1930's.
Wissai