This whole Georgia thing is going to be over pretty quick, I think. Osettia declared their independence, Russia backed them, Georgia attacked Osettia, the Russians followed up on their declarations of support. Georgia's getting their ass whupped, but unless Russia tries to occupy Georgia, the U.S. ain't gonna do jack. We certainly aren't going to go to war with Russia to help Georgia hang on to a separatist region.
Now, if Russia DOES move to occupy Georgia, then we got a problem...
China, isn't going to be a problem, I think. They certainly aren't going to try to take us on over here. We thoroughly outclass them in the air and on the sea, so their massive numerical advantage on land isn't going to help them if they try to attack us here. Basically, they have the troops to whup us good, but if they try to bring them over, they all end up in the drink.
Basically, the worst that is going to happen, and I admit that it is pretty bad, is we get a new cold war...