Yep. This isn't really looking too well. The Ruskies have been making comments about "going beyond diplomacy", and saying that the missile defense system in Poland "cannot go unpunished.".
They've also got their bomber patrols back online again after a 15 year hiatus. Tu-95's and Tu-22(Backfire variant) seem to be on regular patrols now with known intrusions into Canadian and Alaskan airspace. Surprisingly not much activity in the North Atlantic yet (at least not that the public knows about).
Handing the U.S. the bill would mean that the U.S. simply doesn't pay and says, come get it. They are happily using it against us to make sure that we don't interfere in their nefarious chinaman ways. I doubt they want more land mass, they sure as hell don't want more people, they only want Taiwan for revenge on Chiang Kai-shek. So really I can't think of one reason China would want to be involved in a large scale conflict.