I mean that China could beat the US in an all-out war. Hands down.
100 miles of water isn't shit. They have boats, planes, missiles. They don't even need to invade, only to establish a naval/air blockade (in effect a siege) and starve em out.
The Russian military/economy isn't even close to China's. Russia's power lays primarily in its nuclear arsenal, which, thankfully, hasn't been used yet. I'm still waiting for them to use some of their chemical weapons.
China has a lot more bodies. They also have North Korea on a leash, and I have little doubt that Russia and Iran would also be happy to get behind the big dog for a WW3. The only worthwhile allies we've had for the last century are Britain, Australia and Canada, and I see bigger and wider cracks between us every year.
China is THE ascendant world power at the moment, and the US is losing ground fast. Militarily and economically. They will take Taiwan back, one way or another.