I think Australia is allied with the US as a precaution against...

I think Australia is allied with the US as a precaution against an unknown future stretching decades.

We have 3 choices:
1. Continued alliance with the US, the world's most powerful nation determined to prevent China from getting regional hegemony in Asia.
2. Alliance with China, thereby becoming an enemy of the most powerful and ruthless nation on the planet.
3. Becoming neutral.

Only a naive Australian planning to reside here for at least the next decade would choose anything other than the first option for their loved ones and themselves.