USA.
Mr.Scott taught me something in Russia v china thread. Yeah china can have 100,000,000 soldiers mobilized and equipped. But they'd be starving and Ill trained. Meanwhile a Good ol doughboy eats 3 meals a day, is well equipped, well looked after, and is pretty well trained. And that's if China manages to pull a COD modernwarfare two, and get the IFF codes and get through to our coast. Then it has to deal with one of the most well armed trained civilian force in the world. Despite what people think, most Americans aren't fat gun haters, and would fight to the death for this country. And do we really think Japan is gonna pass up an opportunity to use it'd gundams to humiliate the Russians again?
And the argument is moot cause we would basically make china and Russia a non factor in the world by stopping all sea bound trade and bombarding the outta bejing and Moscow. He'll, you unleash the full might of the navy and airforce, and we'll be able to put boots on bejing, not in it.