We just have to persuade them that the cost of offensive operations against Australia is going to be too high
Simple... Australia goes nuclear. All on their own. Even though Australia was a signatory party to the NPT, there's an escape clause. Anyone who previously tested nukes, are not bound to stay non-nuclear. Back in the early 1950s Australia was involved with, and conducted nuclear tests for the mother country UK. Therefore they could quickly develop a nuclear deterrence against China. A deterrence that would not have to depend on the US for nuclear deterrence, if Australia was attacked or even nuked by China.
It isn't a radical idea either. After the Soviet Union fell apart, and Putin came to power with a greatly weakened conventional military force, he let it be known: If you attack Russia with overwhelming conventional forces, we'll nuke ya. Australia could play the same game. Let's not forget N Korea is trying to play that game.
The Jewel of the Mind is Colored with the Hue of what it Imagines
