[Hyperborian]

China also has a very limited air force and barely significant blue water naval capabilities. They are especially lacking in the kind of heavy lifting and transport necessary to make force projection even possible. Due to the size and power of their army and their nuclear capabilities it's safe to say that China is effectively immune to attack (even from the US), but they have a nearly non-existent ability to project force outside of their immediate sphere of influence.

The US, on the other hand, has carrier groups that each have as much military power as many moderately sized nations. And we have ten of them stationed all over the world pretty much all the time. The difference is orders of magnitude.