Since we back these three places, and with North Korea it makes four. Could this be potentially forcing us to split our forces to cover four distant bases with China at the center and in a much better maneuvering position than we are in?
Consider the forces of each of the countries:
South Korea’s army is about as large as ours. Their air force and navy, while not at all comparable to our, are entirely capable of defeating North Korea’s air force and navy. South Korea needs us for strategic deterrence. To prevent China from attempting to bully it.
Japan has navy and air forces are the best in Aria, including China.
India’s army is larger than ours, albeit not with as modern equipment. It’s air force is much smaller and features mostly MIG-21s and Su-30s.
China’s army is twice as large as India’s. Its Air Force has the advantage of more modern aircraft (the J-10, China also has J-7 which is like the MIG-21). But, China would have to project force across Tibet. That is a long and tenuous supply line.