Our navy is four ships half the size of a destroyer, US surplus, and then a whole lot of smaller boats. Our soldiers, airmen and sailors are over trained and extremely competent, but they don't have a lot of toys to play with.
There's less than 4 million people living here. That's not a lot of surplus to sign up to the armed forces or taxes to pay for an armed forces with any scope.
I live in a Banana Republic.
Swap Sheep for banana.
Besides, we all know the secret to winning a game of Risk is holding Australia.
To get to us, Australia has to fall.
How likely is that?