China could replace Russia, and there isn't a lot the people of Central Asia could do about it. Despite that, the Central Asian states believe that the SCO (Shanghai Cooperation Organization) may help keep the Chinese under control. The SCO consists of Russia, China, Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan, with Mongolia, Pakistan, India and Iran as associate members, or "observers". Russia, and the Central Asian states, are trying to get India made a member, as a counterbalance to China. The SCO, unofficially, exists to keep the peace between China and Russia over economic activities in Central Asia. At the moment, China is winning the race to develop large oil and gas fields in Kazakhstan and Turkmenistan. China needs the energy, and is willing to pay whatever it takes. Since the Central Asian nations are run by corrupt leaders, often dictators, the Chinese have an easy, if expensive, way to gaining control of natural resources.
Fear of American (and Japanese, and South Korean, and Indian) naval power interrupting sea lines of communications is leading China to pursue land lines of energy supply as well. But this means that China must now face threats in two directions and in two different forms--sea and land.
This helps direct China away from America at sea, puts China on a collision course with Russia in areas Moscow wants to be dominant and which are dangerously close to core Russia as opposed to the distant Far Eastern provinces.
At worst, with China choosing to become a major land power and naval power (along with air power to support both, of course) to protect these lines of supply, China won't be as effective at sea as they otherwise might be and we will maintain our margin of naval superiority at a higher level and for longer as China builds their navy.
China's power is growing, but they dissipate it with this move into Central Asia and generate a wider reaction of increased balancing military power by neighbors worried about Peking's intentions. So we will remain in good shape even as we lose relative power compared to China.
Being wary of getting involved in a land war in Asia doesn't just apply to America.
