There has been a lot of tension between Russia and China since Stalin and Mao had a falling out. In the 60's there was actually open fighting between the Soviet Union and China on the border. The reason Russia helps China is because they're trying to stay on their good side, as they're very afraid of them.
Basically when I said that I was pointing out that their lack of military equipment and technology compared to ours puts them way behind us in military power, lots of infantry doesn't mean what it used to like I said. Now if they had 50,000 T80's and T90's with a bunch of Su-27's and Mig-29's to support them then maybe it would be a different deal.
